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- ItemAnalgesic and Anti-Inflammatory constituents of annickia polycarpa stem and root barks and clausena anisata root.(AUGUST, 2016) Kumatia, Emmanuel KofiClausena anisata and Annickia polycarpa are medicinal plants used to treat various painful and inflammatory disorders among other ailments in traditional medicine. The aim of this study was to investigate the analgesic/antinociceptive and anti-inflammatory activities of the ethanol extracts of C. anisata root (CRE), A. polycarpa stem (ASE) and root barks (AR) in order to provide scientific justification for their use as anti-inflammatory and analgesic agents. Analgesic activity was evaluated using the hot plate and the acetic acid induced writhing assays. The mechanism of antinociception was evaluated by employing pharmacological antagonism assays at the opioid and cholinergic receptors in the hot plate and the writhing assays. Anti-inflammatory activity was also evaluated by carrageenan induced edema in rats’ paw assay. The compounds were isolated using bioassay-guided fractionation and their structures identified by spectroscopic methods. CRE at 1000 mg/kg p.o. produce significant (p < 0.001) analgesic activity of 72.15 and 48.05 % in the hot plate and writhing assays respectively and significant (p < 0.01) anti-inflammatory activity of 27.53 %. ASE also produced significant (p < 0.001) analgesic activity of 82.54 and 44.03 % in the hot plate and writhing assays respectively and significant anti-inflammatory activity of 69.64 %. Furthermore, the results also showed that the petroleum ether (pet ether) fraction (PEF) of C. anisata root extract and the chloroform fraction (AC) of A. polycarpa stem bark extract were the most active fractions among the petroleum ether, chloroform and aqueous fractions of these extracts. A total of seven (7) compounds were isolated. Four (4) coumarins, namely, anisocoumarin B, osthol, imperatorin and xanthotoxol in addition to a carbazole alkaloid, heptaphyline were isolated from PEF. Two (2) protoberberine alkaloids namely jatrorrhizine and palmatine were also isolated from AC. Palmatine was further isolated from the chloroform fraction of A. polycarpa root bark. The seven isolated compounds were tested for analgesic activity in the writhing test. Six of them at 6 mg/kg p.o., produced significant analgesic activity of 38.13 to 47.28 %. One of the isolates (xantothoxol) was inactive. Analgesic activity of diclofenac in the writhing test was 32.92 % at 6 mg/kg p.o. Four of the isolates were also tested for analgesic activity in the hot plate assay. These isolates at 9 mg/kg p.o. produced immence analgesic effect of 30.13 to 93.87 %. The analgesic effect of tramadol 9 mg/kg p.o. was 27.13 % in the hot plate test.
- ItemAn analysis of a peri-urban sanitation market and farmers’ perception on excreta reuse in agriculture in Dangme West District, Ghana(MAY 2016) Nimoh, FredThis study sought to analyse a peri-urban sanitation market and farmers’ perception on excreta reuse for agricultural purpose in Dangme West District of Ghana. Specifically, the study examined the constraints, motivations and strategies to the operation of sanitation business; analysed financing mechanisms and willingness-to-pay (WTP) for improved household latrines; investigated farmers’ perceptions toward excreta reuse for agricultural purpose; and reviewed literature on regulatory policies for sustainable sanitation. Data were collected using observations, interview guide and survey questionnaire. Descriptive and inferential statistics were used for data analysis and reporting. The motivations and constraints to sanitation business were examined using case sanitation service providers (SSPs). Budgetary estimates and the logit/logistic model were employed to analyse households’ latrine financing decisions, and their WTP for improved household latrines, using the contingent valuation method (CVM). Farmers’ perception on excreta reuse as fertilizer was analysed with a Likert-type scale and the ordered probit model. Results of the study showed that there exist various sanitation-related businesses such as latrine builders/masons, hardware suppliers and pit-emptiers, who operate as sole proprietors in a market characterized as monopolistic competition in the study area. Sanitation business in the study area was found to be profitable, despite the financial, institutional and social challenges to the SSPs’ business. The study found that a majority of the households practise open defecation (ODF), though they prefer improved latrines, particularly the flush latrine and ventilated improved pit (VIP) latrine. Lack of space and funds, availability of alternative option (beach) and no economic value for excreta were mentioned by the households as key considerations to owning a household latrine. A comparison of the households’ income and expenditure showed that the households have sufficient income to finance the construction and management of their latrines, contrary to the claim that they do not have funds to build a household latrine. A majority of households were willing to pay for improved latrines via savings rather than the use of credit, although the financial institutions in the study area are interested to offer loans for household latrines. Empirical results from the logistic model showed that there exists some relationship between households’ latrine financing decisions and their socioeconomic and community characteristics such as gender, education, household composition, income, tenancy, defecation practice and location of community. It was also found that a majority of farmers ‘disagree’ that excreta are a waste and they would use excreta as fertilizer if sterilised; as they ‘agree’ that excreta could pose health risks. Empirical results showed that a farmer’s decision to use excreta as fertilizer is more related to the perception on excreta as a resource, experience in community, household size, income, and land tenure system. Regulatory options identified for sustainable sanitation include the use of community-based organizations, the professional and trade associations, and consumers as 'watch groups'. Based on the findings of the study, the following recommendations, among others, have been made to help improve the Ghanaian peri-urban sanitation: there is the need to address the constraints to sanitation business for effective service delivery. Households should be encouraged to consider the ‘cheaper’ and more feasible latrine technologies, and also adopt joint-resource mobilization strategies for their latrines. Programmes aimed at promoting improved sanitation, in a sustainable manner, should consider the heterogeneous needs and location of households as well as the reuse potential of excreta in agriculture. The choice of regulatory options for sustainable sanitation should be based on a comparative assessment of the trade-offs between effectiveness, ease of implementation and costs and benefits.
- ItemAnticonvulsant and related neuropharmacological effects of a hydro-ethanolic whole plant extract of synedrella nodiflora (L.) gaertn (FAM:Asteraceae).(2011-07-19) Amoateng, PatrickSynedrella nodiflora (L.) Gaertn. (Family: Asteraceae) is an annual herb which grows to about 60-120 cm high and occurs throughout the West African region. In Ghanaian traditional medicine, the whole plant is used for the treatment of epilepsy. This study presents the anticonvulsant, sedative, muscle relaxant, antinociceptive, antioxidant, the effect on anxiety and the safety of a hydro-ethanolic extract of the whole plant of Synedrella nodiflora. Four murine models of experimental epilepsy were employed for the anticonvulsant screening of the extract, namely; pentylenetetrazole-, picrotoxin- and pilocarpine- induced seizure and penetylenetetrazole- induced kindling. The ability of the extract to cause sedation was investigated using the pentobarbitone- induced sleep test. The neuromuscular effects of the extract were also determined in vivo using the rota-rod test and in vitro with the chick biventer cervicis preparation. Moreover, formalin induced pain and acetic acid induced writhing assay were the tests employed to assess the antinociceptive effects of the extract. The antioxidant effects of the extract was also determined by measuring the total phenols, antioxidant capacity, 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging assay, reducing power assay and inhibition of linoleic acid peroxidation. The elevated plus maze, the light/dark test and the Versamax animal monitor were used to investigate the effect of the extract on anxiety in rodents. The acute toxicity test was also done to assess the safety of the extract as herbal medicine. The extract, SNE, showed significant anticonvulsant effect against seizures induced by PTZ by dose dependent increase in both the onset of the myoclonic jerks and latency to myoclonic seizures and a reduction in the duration of seizures. However this effect was not significant compared to the vehicle treated group and not dose dependent. SNE significantly and dose- dependently delayed the latencies to myoclonic jerks and tonic-clonic seizures induced by picrotoxin. SNE also reduced the duration of seizures significantly. SNE also significantly reduced the total frequency of seizures. SNE, also, dose-dependently reduced the total duration of seizures induced by pilocarpine in the mice treated. SNE significantly suppressed the PTZ- kindled seizure at all the dose levels used. SNE (100-1000 mg kg-1) dose-dependently inhibited lipid peroxidation in the PTZ-kindled rats. SNE also, dose-dependently, increased the duration of sleep induced by pentobarbitone in mice. The ability of SNE to attenuate PTZ-, picrotoxin- pilocarpine- induced seizures, PTZ- induced kindling, enhanced sedation of pentobarbitone suggests the possible involvement of GABAergic, anti-cholinergic, or antioxidant mechanism(s). SNE at 1000 mg kg-1 produced a significant reduction in the time spent on the rota-rod at 24 rpm over the two-hour period thus suggesting motor impairment at this dose. Baclofen at 10 mg kg-1 significantly reduced the duration spent by pre-treated mice on the rota-rod. SNE also antagonised acetylcholine- induced contractions in the chick biventer cervicis preparation, thus a neuromuscular blocker. These results suggest a skeletal muscle relaxant effect by S. nodiflora possibly via centrally mediated mechanism(s) involving neuromuscular blockade. In the formalin-induced pain and the acetic acid- induced writhing, morphine and diclofenac were used as standard opioid and NSAID respectively. The hydro-ethanolic extract of S. nodiflora (100-1000 mg kg-1, p.o) and morphine (1-10 mg kg-1) dose-dependently decreased both phases of the formalin-induced nociceptive behavior. The antinociceptive effects of S. nodiflora (300 mg kg-1, p.o) on the first and second phases of formalin-induced pain were significantly blocked by caffeine but not by naloxone. In the acetic acid-induced writhing test, diclofenac and S. nodiflora significantly reduced the number of writhes dose-dependently. Also, the effect of the S. nodiflora (300 mg kg-1) was blocked by caffeine (3 mg kg-1) but the analgesic effect of diclofenac was significantly enhanced. The observed effects of caffeine on the central and peripheral analgesic effects of S. nodiflora in the formalin and acetic acid- induced writhing suggest the possible involvement of adenosinergic mechanism(s). The extract (0.1-3.0 mg ml-1 ) was found to contain phenolic compounds which could be responsible for the antioxidant properties. The extract also exhibited antioxidant properties by reducing Fe3+ to Fe2+ in the reducing power test, scavenged DPPH free radicals and effectively inhibited linoleic acid autoxidation. In the EPM paradigm, S. nodiflora extract (10-300 mg kg-1) exhibited anxiogenic-like activity by dose-dependently decreasing the number of entries into both the open and closed arms, no significant effect on the percent number of entry into the open arms and a decrease in the time spent in the open arm in comparison to the vehicle-treated group. Similarly, S. nodiflora extract (SNE) dose-dependently decreased the number of head dips and stretch-attend postures and the duration of grooming. In the LD test, SNE also exhibited anxiogenic-like effect by significantly and dose-dependently reducing the number of entry into the light compartment, the number of transitions and not significantly, the time spent in the light area. In the EPM and LD test, diazepam (0.1-1.0 mg kg-1), a reference anxiolytic drug, produced a directly opposite response to that exhibited by SNE. The extract, in the VAMS, decreased the locomotor activity of pretreated-mice dose dependently and significantly. SNE reduced the distance travelled and time spent at the center of the observation cage indicating an anxiogenic-like effect. The extract‟s ability to cause a general reduction in locomotor activity suggests sedative effects rather than anxiogenesis. Oral administration of SNE (1000-10,000 mg kg-1) yielded no mortality in the treated mice over a 24 h of observation. Thus the LD50 was approximated to be greater than 10,000 mg kg-1. Thus the extract can be said of as being less toxic. Also high protective indexes produce in the PTZ-, picrotoxin- and pilocarpine-induced seizures by the extract suggest that it has a safe therapeutic profile. In conclusion, the hydro-ethanolic extract of S. nodiflora has anticonvulsant effect in the acute and chronic seizure models of epilepsy used and indicates a possible GABAergic mechanism(s); exhibits central analgesic effect possibly mediated through adenosinergic mechanism and a peripheral anti-inflammatory activity and a potent antioxidant and free radical scavenger, a muscle relaxant and has anxiogenic-like and sedation effects.
- ItemAntiplasmodial compounds from Ghanaian medicinal plants(December 2015) Komlaga, GustavMalaria is a major public health challenge in Ghana, and many indigenes employ medicinal plants, beside orthodox medicines, to treat the disease. An ethnobotanical survey was performed in the Bosomtwi and Sekyere East Districts of Ghana to identify plants used locally to manage malaria. This was done in comparison with the plant ingredients in marketed herbal antimalarial remedies in the Kumasi metropolis. The survey inventoried ninety-eight (98) plant species; twelve (12; 12.2%) reported for the first time globally, and twenty (20; 20.4%) others for the first time in Ghana for the treatment of malaria. Twenty-three (23) locally available finished, often multi/polyherbal antimalarial products examined contained aerial or underground parts of twenty-nine (29) of the plants cited in the survey as ingredients. Twenty-two (22) of these products were registered by the Ghana Food and Drugs Authority; four (4) were included in the Ghana Health Service recommended herbal medicine list for treating malaria in Ghana. The aqueous as well as serially extracted organic solvents (petroleum ether, ethyl acetate, and methanol) extracts of five plants parts, selected based on their importance in the traditional treatment of malaria and lack of the appropriate data in the literature, were studied against the chloroquine-sensitive 3D7 and chloroquine-resistant W2 P. falciparum parasite in vitro. The plant materials included the whole of Phyllanthus fraternus, leaves of Tectona grandis, Terminalia ivorensis and Bambusa vulgaris, and root of Senna siamea. All the aqueous extracts showed notable antiplasmodial activity (IC50 < 10 µg/mL), except that of S. siamea, against 3D7 P. falciparum. Only T. ivorensis and S. siamea extracts showed activity against W2 P. falciparum (IC50 < 50 µg/mL). The extracts demonstrated high selectivity index (SI) for 3D7 P. falciparum (SI > 3.5) but very low SI for W2 P. falciparum. Resistance index (RI) was largely under 20. The organic fractions were equally active (IC50 < 50 µg/mL; 3D7 P. falciparum). The methanol extracts of the two most potent plant materials, the whole of P. fraternus and leaf of B. vulgaris, were subjected to phytochemical study to isolate and elucidate the chemical constituents, which were then assayed for antiplasmodial activity. The phytochemical study of the v methanol extract of P. fraternus yielded six compounds; Pf 1 to Pf 6 identified as the lignan, phyllanthin, and five securinega alkaloids namely nirurine, ent-norsecurinine, allo-norsecurinine, bubbialine and epibubbialine. This is the first isolation of allo - norsecurinine from a natural source and bubbialine from the Phyllanthus genus. The compounds displayed significant antiplasmodial activity against both 3D7 and W2 P. falciparum (1.14 ± 0.32 µM ≤ IC50 ≤ 59.00 ± 5.43 µM); ent-norsecurinine being the most active (IC50=1.14± 0.32 µM) and against the W2 P. falciparum. Only Pf2 (nirurine) and Pf1 (phyllanthin) displayed cytotoxicity (CC50 < 100 μM; HUVECs). This is the first report of the antiplasmodial activity of these compounds. Similar study of the methanol extract of B. vulgaris yielded 6 compounds, Bv1 to Bv6, identified as p-coumaric acid [(E)-3-(4-hydroxyphenyl) acrylic acid], cinnamic acid, dehydrovomifoliol [(E)-4-hydroxy-3,5,5-trimethyl-4-(3-oxobut-1-en-1-yl)cyclohex- 2-en-1-one], 3-oxo-α-ionol [9-hydroxy megastigma-4, 7-dien-3-one], loliolide [6- hydroxy-4, 4, 7a-trimethyl-5, 6, 7, 7a-tetrahydrobenzofuran-2(4H)-one] and tricin [5,7,4’-trihydroxy-3’,5’-dimethoxyflavone]. The six compounds are the first everreported isolations from B. vulgaris. All the compounds from B. vulgaris displayed significant activity against 3D7 (IC50 < 5 μΜ and W2 strains of P. falciparum (IC50 < 7 μM). Bv1 (p-coumaric acid) was the most active against 3D7 P. falciparum (IC50: 0.84 ± 0.90 μM) and Bv2 (cinnamic acid) the most active against W2 P. falciparum (IC50: 1.41 ± 0.38 μM). The compounds displayed no cytotoxicity (CC50 > 100 μM; HUVECs). This is the first report of the antiplasmodial activity of the six compounds. These twelve (12) compounds with remarkable antiplasmodial activity add to the library of natural compounds with antiplasmodial activity. This study has illustrated the potentials of Ghanaian medicinal plants as source of natural antiplasmodial compounds, and has justified the use of the plants in traditional treatment of malaria.
- ItemAspects of the ecology of noack’s roundleaf bat (Hipposideros Aff. Ruber) in Ghana(2014-07-20) Nkrumah, Evans EwaldThe roost of bats in five caves in the central parts of Ghana were investigated. A total of 10,226 bats belonging to nine species were mist-netted within two years. There was a significant difference in species composition of the caves. The Noacks’s roundleaf bat, Hipposideros aff. ruber was found to be the most dominant species roosting inside the cave and some aspects of its ecology were further investigated. The flight activity of Hipposideros aff. ruber was limited to certain periods of the night at Kwamang cave one while it was uniform at Kwamang cave two. The estimated mean home range size of this species using radio-tracking was thirty-six hectares with a foraging range of 1.2 km. There was no significant difference in the home range sizes of the males and females. Hipposideros aff. ruber used 50% of its home range as the foraging area and 2% as the core area. Pregnant females had smaller home ranges and foraged not more than 0.2 km away from the roost cave. Hipposideros aff. ruber used all available habitats around its roost but strongly preferred to forage in fallow lands ahead of other habitats. This bat used tree farms such as cocoa as flight paths to commute between roost caves and foraging areas and exhibited a trimodal activity pattern foraging at dusk, midnight and dawn. Hipposideros aff. ruber is a strong flyer commuting over longer distances. A three kilometre radius around its roost should be included in the protection of its home range. In highly impacted agricultural landscapes, fallow lands are recommended as conservation units to support this bat. In such landscapes, provision of canopy trees as flight paths is recommended to allow them to commute between roost and habitats that support higher prey densities
- ItemThe attitudes and perceptions of students about the study of english grammar: the case of selected senior high school students in northern region(2015-05-22) Akurugu, Brigandi MichealThe poor quality of English, both spoken and written, of Ghanaians in general, and of our students in particular, has become a source of worry to many well meaning educationists, parents and the general public. Several reasons have been given for the falling standards. Included among them are reading habits, poor teaching, inadequate library facilities, decline in the teaching of grammar and the de-emphasis of the mother tongue as the medium of instruction. There are those who believe that the use of the mother tongue at the basic level of education helps the learner to relate similar grammatical concepts in the L1 to those of the English Language. Much as the aforementioned could be said to be accountable, there is a fundamental phenomenon that acts as the underlying cause of the problem. The role that perception and attitude of the learners plays in the acquisition of skills in English has, over the years, been terribly ignored. The perception of students, teachers, policy makers, and the larger community, which includes parents, has played a considerable role in bringing about the fall in the standard of English. This study investigates the extent to which the fall in the standards of English could be attributed to attitudes and perceptions. The study has revealed that a serious disconnection exists between the needs of students and the solutions that are being used to raise the standard of English Language among learners. The study also reveals that, in most cases, parents, teachers and policymakers cannot escape blame for the problem either for their action or inaction regarding the promotion of the learning of the language. Though the study may have identified other reasons for the decline in the standards of English, the study focuses, to a large extent, on the very attitude and perception of the learner. It has suggested ways of developing positive perceptions and attitudes v towards the language. These suggestions include sound approaches to the teaching and learning of the language. The approach is carved in a manner that would make English more attractive to learners thus leading to attitudinal and perceptual change, which in turn would lead to enhanced performance of learners in English.
- ItemCompatibility of Jatropha Curcas in an Agroforestry System(2015-04-20) Abugre, SimonJatropha curcas is gaining importance as a potential biofuel crop in Ghana. Already skeptics are talking about the impact of the crop on food crops. It is important that the compatibility of J. curcas in agroforestry systems is investigated to provide answers to some of the potential problems being advanced. Experiments were conducted to determine the compatibility of J. curcas on the growth and yield performance of Zea mays. To determine the growth and yield of Z. mays under J. curcas hedgerows, an experiment using a Randomized Complete Block Design (RCBD) with three hedgerow spacings of 2 m x 1 m, 3 m x 1 m, 4 m x 1 m of J. curcas and a control (No hedgerow) was conducted. This was replicated 3 times. The results of the study showed that J. curcas spacing had no significant effect (P ≥ 0.05) on plant height, plant diameter, number of leaves and number of nodes/plant of maize in the first year. In the second year, however, increases in plant height of 17.19%, 22.39% and 23.38% were realized for 3 m x 1 m, 4 m x 1 m and the control (No hedgerow) respectively with respect to 2 m x 1 m. Diameter at first node however, increased by 19.69%, 16.87% and 18.46% for control, 3 m x 1 m and 4 m x 1 m respectively with respect to 2 m x 1 m. Maximum grain yield of maize was 4.47 tons/ha in the first year at the control treatment, which differed significantly from the 2 m x 1 m, 3 m x 1 m, 4 m x 1 m treatments. Chemical properties of the soil did not record any significant decline after two years of cultivation for pH, organic carbon, total nitrogen, organic matter, exchangeable cations, total exchangeable bases, exchangeable acids and base saturation. The highest Land Equivalent Ratio (LER) was recorded at 4 m x 1 m for both years, making it the most suitable plant spacing for J. curcas with maize while the highest economic returns were obtained at 4m x 1m and 3m x 1m spacing. The influence of storage period, fertilizer and spacing on the growth and yield of J. curcas propagated from seed were evaluated in a second experiment using two different designs. Seeds of J. curcas were stored for 1 to 12 months, sown on beds in a RCBD,replicated four times and their viability and germination energy tested. The results showed a progressive decline in germination from 98% after one month to 52% when stored for 12 months. The highest germination energy was obtained during the first two months of storage. Fertilizer and spacing effects were also evaluated in a split plot design in RCBD and replicated three times. Three plant spacings (D1=1m x 1m; D2=2m x 1m; D3=3m x 1m) and two fertilizer application levels (F0: 0kgNPK/ha, F1: 150kgNPK/ha) were used. Fertilizer and spacing interaction did not significantly (P ≥ 0.05) affect yield components of J. curcas. The fertilizer treatment however, had a significant effect on yield components and increased seed and fruit yield by 56.4% and 51.75% respectively. Spacing did not significantly affect seed yield. A third experiment on the variation in seed sources of J. curcas and polybag size on the growth of seedlings was laid out using a split plot design in RCBD with 3 replicates. The results showed significant variation in seed weight from the various seed sources but no differences in seed length and seed width. Seedling growth of J. curcas was highest when larger polybag size was used, however, it did not differ significantly from medium polybag size. Based on the results obtained medium polybag size would be ideal for raising seedlings. In a fourth experiment the decomposition trend of J. curcas leaves was assessed by placing 80 g fresh leaves in a 0.30 m x 0.30 m nylon litter decomposition bags of 2 mm mesh size under closed and open canopies. The total quantity of litter produced in a year at different spacings were 2.27 ton/ha, 1.10 tons/ha and 0.79 tons/ha for 1 m x 1m, 2 m x 1m and 3 m x 1m, respectively. The month of November had the highest litter fall (508.8 kg/ha) for 1 m x 1 m. J. curcas under open canopy had 97-99% of leaf litter decomposing by the end of the experimental period and a half-life of 25 days. Open canopy had the highest decomposition constant (k) of 0.020. In a final experiment the effect of aqueous extracts from leaves and roots of J. curcas on four traditional crops (Phaseolus vulgaris, Zea mais, Lycopersicon lycopersicum and Abelmoschus esculentus was examined. Aqueousextracts at concentrations of 2%, 4%, 6%, 8% and 10% applied to the test crops affected all the crops. Extracts at higher concentrations of J. curcas had a strong inhibitory effect on germination, radicle and plumule length of all the test crops. The inhibitory effect suggests the presence of allelochemicals that could inhibit the growth of the crops. Generally, it can be concluded that J. curcas is compatible with maize in an alley cropping system but closer spacing of planting J. curcas can reduce maize yields. Management practices such as pruning could be applied to get the optimum benefit from the system.
- ItemThe Contributions of International Development partners to rural poverty reduction in Ghana: a case study of the International Fund for Agricultural Development (ifad) and small-holder farming in the Sekyere-West District, Ashanti Region(2009-07-15) Asamoah K., KennedyAlthough available statistics in recent years reveal a decline in poverty in Ghana, many people still live below the poverty line. Rural small-holder food crops farmers are the most vulnerable groups affected by poverty. They have limited access to productive assets, most especially micro-credit. Many international development organisations have emerged to help alleviate some of the problems encountered by the rural poor. The International Fund for Agricultural Development (IFAD) as an international development partner in Ghana, has been working with small-holder farmers in the Sekyere West District since 2000 with the aim of improving rural income, reducing vulnerability, ensuring rural household food security and generally improving the well-being of the rural poor. This thesis examines the effects of IFAD’s project on food crops production, employment as well as income levels and the general welfare of small-holder farmers in the District. A random sample size of 240 IFAD assisted farmers in the District was used to undertake the study. Cross-sectional data covering the farming years (2000 – 2004) were elicited from the farmers through structured interviews and focus group discussions. Information such as sources of financing, farm input, farm size, crop yields and income levels were sought from the farmers. The study revealed that IFAD, as enshrined in its policy statement of ensuring gender equity in the distribution of its resources/assistance (IFAD, 2000), equal number of male as that of female small-holder farmers (approximately 50-50 respectively) were selected in the District to participate in the project. The study also showed that majority of the farmers interviewed depended on farm income as their main source of subsistence. Micro-credit provision was particularly seen as the most important factor influencing food crops production in the District. The study also showed that the effective training and monitoring activities of IFAD field staff ensured that resources given out to the farmers were not misappropriated. The study showed that the project registered a high food crops production rate as well as a high loan repayment rate of the farmers. Furthermore, the study revealed that the average income of beneficiary farmers increased considerably over the project period due to the good marketing strategy introduced by the project. Based on the findings of the study, it was recommended that the government should adopt and replicate the IFAD intervention scheme in all the other districts in Ghana since the project could have a multiplier effect on the livelihood of the rural poor especially the small-holder farmers.
- ItemControl of pregnancy-associated malaria through community involvement in rural Ghana(2009-6) Bam, Victoria BubunyoMissing Page
- ItemEnterprise Resource Planning (ERP) Implementation in a Sub-Saharan African Nation: An Empirical Test of Competing Models and Theories(May, 2014) Asamoah, DavidIn this study, the researcher developed a modified research model to examine the antecedents and impact of extent of Enterprise Resource Planning (ERP) systems implementation on Process Management Capability, and its subsequent impact on firm performance. The existing model was extended by the addition of the following constructs: Ethical Factors, Data Culture, Organizational Integration, and Organizational Performance. In exploring ERP implementation in Ghana, a Sub-Saharan African (SSA) nation, two competing theories, the Institutional theory and the Panoptic theory, were tested using empirical data collected from a survey involving 115 respondents from organizations in Ghana that had implemented ERP systems. The data was analyzed using structural equation modeling-partial least squares. The findings indicate that the Panoptic theory explains the relationships between the constructs better and confirms the positive impact of higher extent of ERP implementation on process management capabilities. Theoretical implications of the study include (1) the emergence of the Panoptic theory as a strong predictor of ERP implementation in SSA (2) the mediating effect of the Ethical factors and Organizational Integration (3) the panoptic theory has more predictability and can be more easily generalized than institutional theory, allowing the research to have a more global impact beyond SSA and (4) Contextual factors such as industry type, employee size, and ERP type influence ERP implementations in SSA. Practical Implications are: (1) ERP systems create information visibility which checks the ethical behaviour of employees and causes them to behave in a socially responsible manner (2) Organizations can achieve greater organizational integration by increasing their extent of ERP implementation and (3) Governments and regulatory bodies must institute policies and protocols that encourage ERP adoption.
- ItemEvaluating the effect of stone bunds erosion control on vegetation trend in South-West Burkina Faso - A fine scale remote sensing perspective in the Ioba Province(November, 2019) Asare, Yaw MensahSoil erosion by water has become a worldwide issue due to its environmental and socioeconomic impact in the light of rising concerns over climate change. To minimize the impact of soil erosion by water in West Africa, several erosion control measures have been adopted and are being practiced. The type of erosion control measure practiced depends on the climatic zone in which the area falls. In South-West Burkina Faso where this study was undertaken, rainfall is relatively high compared to the other areas within the country. As a result, the use of stone bunds/lines is the most commonly practiced erosion control measure. But after the implementation of these erosion controls, very little has been done on evaluating the impact of these erosion controls on vegetation (crops and natural vegetation) improvement using remote sensing data. This is because until recently, organized erosion control measures more especially using stone bunds over thousands of hectares of both agriculture and non-agriculture lands was rare. This study, therefore, investigated the effect of stone bunds erosion control measure on vegetation trend using remote sensing data. A time series analysis of NDVI data from 2004 to 2017 was conducted to find: (i) the trend of vegetation in the whole study area and (ii) the trend of vegetation in areas with stone bunds erosion control and areas without. Subsequently, a comparison using the ANOVA test was done between the trends of NDVI in these two areas. Also, a seasonal analysis of the crop heights of cotton and millet was conducted using photographs from UAV. Lastly, a pixel-wise trend was conducted for climate variables (rainfall and temperature) and a correlation analysis was also performed between NDVI and climate variable time series. The results showed that, the NDVI trend of the whole study area is significantly increasing at a rate of 3.7 x 10-4 ΔNDVI/month at 95% confidence interval (CI). Similarly, areas with stone bunds erosion control and areas without stone bunds erosion control had significant increasing trends ranging from 3.14 x 10-4 to 3.95 x 10-4 ΔNDVI/month and 3.83 x 10-4 to 3.91 x 10-4 ΔNDVI/month respectively. In comparing the NDVI trends of the two areas, the result from the ANOVA test showed that there is no significant difference between the NDVI trends of areas with stone bunds erosion control and areas without stone bunds erosion control (p-value = 0.319). Although, the mean NDVI trends for the whole area gave a positive trend, the results of the pixel-wise analysis showed that, positive, stable and negative NDVI trends were widespread in the study area with a range of -0.001 to a maximum of 0.002 ΔNDVI/month. Only 10.6% of the NDVI trends was statistically significant at 95% CI. In comparing the crop heights in areas with stone bunds erosion control and areas without, at 95% CI, the t-test revealed that there is no significant difference between the means of the crop heights of cotton (p-value = 0.389) and millet (p-value = 0.884) in these two areas. For trends of climate variables, rainfall and temperature had a positive increase in the monthly trend of 0.12mm/month and 0.01°C/month respectively. In terms of the correlation between NDVI and climate variables, there was a positive correlation between NDVI and rainfall (Kendall τ of 0.513), whiles a negative correlation (τ = -0.322) was observed between NDVI and temperature. The results from this study will help future studies of evaluation of erosion control measures in West Africa. By combining data from other satellites such as the Sentinel, this will go a long way to help to bridge the problem of data availability for vegetation time series analysis.
- ItemEvaluating the role of the Ghanaian pharmacist in medication safety strategies in hospitals(2015-11-04) Acheampong, FranklineHealthcare has always been a risky venture with a lot of harm associated with it. Medicines form a major and vital part of the healthcare delivery system. The World Health Organisation and many national safety organisations have created a lot of awareness about the importance of enhancing patient safety in the healthcare system. Evidence available suggests that a lot of adverse drug events especially medication administration errors occur during the medication use process. Consequently, it is important to detect and prevent errors at the drug administration stage, since it is also the last step before these errors could reach patients. In Ghana, little is known of the prevalence and contributory factors of medication administration errors. Current literature suggests the existence of many medication safety strategies that are being employed. Pharmacists in particular, have been identified to contribute immensely to the safe use of medicines globally. The aim of this study was to determine the existence of adverse drug events with emphasis on medication administration errors, explore the perceived roles and documented evidences of pharmacists’ roles in the safe use of medicines and understand the experiences and expectations of doctors and nurses on such roles. Methods The methods used were the following: • A direct non-participatory observation of medication administration by nurses followed by face-to-face interview with a sample of these nurses at the Surgical Medical Emergency Department of Korle Bu Teaching Hospital. • Survey of pharmacists working in Ghanaian hospitals across the country using a structured questionnaire. • Retrospective evaluation of documented clinical intervention reports followed by key informant interviews of pharmacists involved in the reporting. • Open and close-ended questionnaires administered to a conveniently sampled doctors and nurses at the hospital to explore their perceptions and expectations. Key findings • Medication administration errors occurred at a rate of 27.2% at the emergency setting. It was also shown that most of the causes of the errors were related to staff and environmental factors such as workload, and lack of adequate knowledge about medication and their use. • Pharmacists in Ghanaian hospitals perceived their services to be useful in preventing adverse drug events. They indicated that they spent more time on activities with perceived greatest impact on patient care such as reviewing pharmacotherapies, monitoring adverse drug reactions and counselling patients on medication use. • Documented evidence of Pharmacist’s clinical interventions activities revealed that 24 pharmacists made 1019 clinical interventions in 448 handwritten reports. Majority (76.1%) of the interventions related to drug therapy changes. The pharmacists reported that the major barrier to their medication safety roles was the perceived discrepant attitude of doctors and nurses. • In contrast, doctors and nurses indicated that they interacted frequently with pharmacists and acknowledged their roles to be useful in contributing to medication safety. Conclusions and Recommendations • Medication administration errors were observed in over a quarter of the activities of the nurses involved in the study. • There was an overwhelming evidence of the strategic role of hospital pharmacists in identifying and preventing adverse drug events. • Unlike the perception that pharmacists had about the discrepant attitudes of doctors and nurses, the clinicians acknowledged and appreciated the role of the pharmacist in medication safety. • The clinical role of pharmacist in hospitals should be intensified to enhance safety and patient care.
- ItemFramework Development for Integrating Information and Communication Technologies Into The Ghanaian Senior High School Visual Art Curriculum(2010-07-15) Degraft-Yankson, PatriqueWithin the past decade, efforts at integrating ICT into the school curriculum have become popular in the country's educational institutions. Even before the government of Ghana, on the basis of the Anamuah-Mensah committee on education, recommended ICT infusion into the educational system, there were far-flung ICT integration attempts initiated by Parent/Teacher Associations, Old Students Associations, non-governmental organizations and some ICT related establishments. This indeed is a clear manifestation of how conscious Ghanaians have become about the importance of ICT in institutions of learning. Unfortunately, however, a close observation of the emergence of ICTs in Ghanaian Senior High Schools seems to lack definite goals for teaching and learning. Besides, attempts at ICT integration are happening so independently that the extent to which its infusion or introduction (to phrase itrealistically) is benefiting education of the students is uncertain. It is for this reason that a Curriculum Framework aimed at developing the use of ICTs in the teaching and learning of Visual Arts in Ghanaian senior high schools is considered essential. This study begins with an examination of the opinions and knowledge base of Art teachers and students about ICT and Art Education. It also explores the educational goals of existing ICT progarmmes in Ghanaian Senior High Schools which focus on conventional computing that only enables students to use a narrow range of software that have very little benefit for the Visual Art student in particular. The study further seeks the views of ICT experts, curriculum planners/reviewers, teachers and other stake holders concerning effective integration of ICT into the teaching and learning of visual arts in the senior high schools. Two key dimensions emerged from the views sampled from Visual Art teachers, students, curriculum reviewers and ICT experts: (1) Motivation for ICT integration and usage, based on (2) Curricular and pedagogical innovations. Despite the divergence in opinions, beliefs and attitudes, Visual Art teachers and students seem ready and highly motivated by the promises of new technologies to use ICTs. However, this can be possible only when efforts are formally put in place to ensure innovations in pedagogy through a qualitative change in the existing Visual Art curriculum. The outcome of the investigations formed the rationale for developing a Framework for Integrating ICTs into the Ghanaian Senior High Schools Visual Art Curriculum. The framework aims at exposing students in the Visual Arts to relevant basic skills that are required to develop their computer literacy skills beyond word processing, ultimately developing their creative thinking skills through information and communication technology.
- ItemHousehold Energy, Coping Strategies and Health Effects in the Bongo District of Ghana(2009-07-14) Odoi -Agyarko, Aba ObrumahCurrently millions of people around the globe rely on wood as a source of fuel for cooking. Although this situation not only pertains to impoverished rural communities, it is within these communities and in developing countries like Ghana that this is occurring the most. The burning of wood in open fires is causing a number of health problems but is also deteriorating for the rural household economy as well as for the local and global environment. Women and children are the main groups exposed to the indoor smoke produced while cooking. Illnesses as a result of this exposure take millions of lives every year. This thesis looks into the relationship between rural household energy consumption patterns, coping strategies and health effects for domestic cooking in the Bongo district in the Upper East Region of Ghana. Several methods including household survey; focus group discussion and key informant interviews were employed to collect data at household and individual levels. The methods involved queries on several aspects of household energy consumption. The survey of household energy consumption pattern was carried out in fifteen communities comprising of 625 households between January-April 2006. The households surveyed covered heterogeneous population belonging to different income, educational and social groups. Daily average concentrations of respirable particulates and carbon monoxide from woodsmoke in 45 rural homes selected through stratified random sampling from the Bongo district in Ghana was also quantified using UCB Particle Monitors. CO was measured with Onset HOBO Loggers. Graphical, cross-tabulation and multinomial logistic regression methods are applied to data drawn from Household Survey. The results indicated that there was more availability and utilization of solid biomass fuels as energy resources in domestic sector as compared to the commercial fuels. Crop residues, firewood and Charcoal were found to be the three main fuels used for cooking, though LPG was also used along with biomass fuels. But complete conversion to cleaner fuels has not taken place yet even in households that has been using LPG for many years. Income was an important factor determining the choice of fuel for cooking, but there were some socio-cultural factors which were equally important in making fuel preferences at household level. The use of biomass fuels; from it collection to combustion also has impacts on the health of the user. Result from the woodsmoke monitoring shows that the values of respirable particles (PM2.5) ranged from 0.05–6 _g.39mg/m3 and 2.90- 45.60ppm for CO. Both PM2.5 and CO concentrations were well above both the World Health Organisation 24-hour Guideline and Interim Targets. Observed health effects from the collection and use of biofuels included eye discomfort, headache, backache, coughing, skin irritation, stiff necks and chest pains. Extrapolation of diseases with PM concentration showed that households were in a higher risk of being infected with respiratory diseases from the use of biomass fuels. This observation confirms with the self-reported symptoms associated with biomass fuel use where respiratory diseases dominated (cough, wheezing, shortness of breath, eye irritation). Considering that traditional biomass will likely continue to be the most popular cooking fuel in rural areas of the district in the near future, and that households can achieve considerable welfare gains from improvement in stoves and kitchen ventilation, the analysis suggests that the government should consider reviving the improved stove program with a new advanced stove strategy coupled with conducting advocacy campaigns on how to improve kitchen ventilation.
- ItemAn In Vitro Model of Endemic Burkitt’s Lymphoma (eBL) Pathogenesis; Cooperation of Plasmodium Falciparum and Epstein Barr Virus in DNA Damage Mediated Via Activation Induced Cytidine Deaminase.(2012-06-15) Ayivor-Djanie, ReubenPlasmodium falciparum (P. falciparum) and Epstein-Barr virus (EBV) infections are contributors in the pathogenesis of endemic Burkitt’s lymphoma (eBL), although the precise mechanism of their synergy remains elusive. Reports suggest that the role of P. falciparum is indirect, creating a permissive environment for the outgrowth of EBV. EBV on the other hand invades and immortalizes lymphocytes in vitro and upregulates activation-induced cytidine deaminase (AID), a DNA repair enzyme responsible for diversifying the antibody repertoire and a potent mutagen capable of inducing the genetic damage characteristic of eBL. It is yet to be shown how exposure to P. falciparum affects the expression of AID in lymphocytes. The aim of this work was to investigate the possible direct role of P. falciparum in eBL lymphomagenesis by exploring parasite-lymphocyte interactions and AID expression after exposure to P. falciparum and/or EBV. Malaria positive slides were examined for parasite-lymphocyte interactions and primary tonsillar mononuclear cells (MNCs) were co-cultured with RBCs infected with up to 5% parasitemia of the 3D7 strain of P. falciparum. Geimsa stained thin smears were made from these co-cultures and examined for parasite-MNC interactions over a five day period. No direct parasite-MNC interaction was observed from all slides examined. The levels of AID mRNA in MNCs was measured by qPCR after in vitro exposure to P. falciparum and/or EBV, and in the presence or absence of 2µg/ml cyclosporine. P. falciparum induced up to a 6-fold increase in AID over unstimulated controls, EBV induced a 13-fold maximum increase, and both pathogens together induced up to a 22-fold increase in AID. With cyclosporine, AID mRNA levels in the P. falciparum stimulated cultures remained unchanged. EBV alone induced a 22- fold increase in AID and both pathogens together induced a 42-fold increase in AID. DNA damage was estimated by Comet Assay and quantified with an algorithm from the Comet Assay Project Lab (CASP). DNA comets revealed that P. falciparum induced moderate DNA damage in MNCs with up to 5.6% and 10% DNA in tails of comets with and without cyclosporine respectively. Cultures stimulated with EBV recorded DNA damage of up to 16% and 13% DNA in tails of comets with and without cyclosporine respectively; and both pathogens induced DNA damage with up to 11% and 16% DNA in tails of comets with and without cyclosporine respectively. The levels of DNA damage in these cells correlated with AID levels and demonstrate that P. falciparum plays a direct role in eBL pathogenesis, by inducing AID expression to levels similar to that expressed in BL cells and cooperating with EBV to induce abnormally high levels of AID and DNA damage.
- ItemThe kinetics of mycolactone in relation to the microbiological, clinical and immunological responses to antibiotic therapy for mycobacterium ulcerans disease.(2014-11-20) Sarfo, Fred StephenBackground: Mycobacterium ulcerans is the causative agent for a chronic necrotising skin infection called Buruli ulcer. Pathology of the disease is closely linked with the elaboration of a unique lipid toxin, mycolactone, which has potent cytotoxic and immunomodulatory properties. In this study, assays were developed to detect and quantify mycolactone concentrations in tissues during curative antibiotic therapy in mice and in humans to understand its dynamics in pathogenesis and to explore its potential as a biomarker for diagnosis and monitoring of patients with Buruli ulcer disease on antibiotic therapy. The currently recommended antibiotic regimen for the management of Buruli ulcer is a combination of daily intramuscular injections of streptomycin and oral rifampicin for 8 weeks (RS8). This regimen was compared with streptomycin/rifampicin for 2 weeks followed by clarithromycin/rifampicin (RS2RC6) for 6 weeks in patients to determine the clinical and bacteriological effectiveness in a pilot study. Methods: Biopsies were obtained from infected human skin tissues and BALB/c mouse hind footpads before, during and after 8-weeks of rifampicin-containing combination antibiotic therapy. Lipids were extracted from tissues using organic solvents, mycolactone concentrations were measured using a cytotoxicity assay and mass spectrometry. Trends in mycolactone concentrations and clinical, bacteriological and immuno-histopathological responses were determined. Concentrations of cytokines in supernates of whole blood assays in humans or murine splenocytes after stimulation with mycobacterial antigens/T-cell mitogens were measured using ELISA. iv Results: Eighty-three patients with confirmed Buruli ulcer were randomized to RS8 or RS2RC6 and monitored for recurrence free-healing. Bacterial load in tissue samples before and after treatment for 6 and 12 weeks was monitored in samples obtained by 4mm punch biopsy by semi-quantitative culture. There was no difference in using RS8 or RS2RC6 with respect to healing rate or the proportion healed in each group after 4, 8, 12, 16, 20, 24 and up to 52 weeks. The success rate was 93% in each group and there was no recurrence after 12-month follow-up. There was no difference in the number of bacteria cultured at the different time points for the two regimens. Mycolactone was detectable in 92% and 77% of human samples (n=80) using cytotoxicity assays and mass spectrometry respectively. Antibiotic therapy was associated with a decline in tissue concentration of mycolactone in both human and murine-infected tissues which was paralleled by resolution of clinical lesions, reductions in bacteriological counts and restoration of local and systemic immune responses. Discussions/Conclusions: This study shows that mycolactone concentrations in tissues is closely associated with the presence of M. ulcerans and provides useful proof-of-concept data that mycolactone detection could potentially be used to monitor response to antibiotic therapy as well as for diagnosis of Buruli ulcer disease. The findings from the pilot study indicate that rifampicin combined with clarithromycin can replace rifampicin and streptomycin for the continuation phase after rifampicin-streptomycin treatment for 2 weeks without any apparent loss of efficacy. The implication is that a controlled trial of fully oral therapy using rifampicin and clarithromycin for 8 weeks (RC8) is justified.
- ItemThe kinetics of mycolactone in relation to the microbiological, clinical and immunological responses to antibiotic therapy for mycobacterium ulcerans disease.(2014) Sarfo, Fred StephenBackground: Mycobacterium ulcerans is the causative agent for a chronic necrotising skin infection called Buruli ulcer. Pathology of the disease is closely linked with the elaboration of a unique lipid toxin, mycolactone, which has potent cytotoxic and immunomodulatory properties. In this study, assays were developed to detect and quantify mycolactone concentrations in tissues during curative antibiotic therapy in mice and in humans to understand its dynamics in pathogenesis and to explore its potential as a biomarker for diagnosis and monitoring of patients with Buruli ulcer disease on antibiotic therapy. The currently recommended antibiotic regimen for the management of Buruli ulcer is a combination of daily intramuscular injections of streptomycin and oral rifampicin for 8 weeks (RS8). This regimen was compared with streptomycin/rifampicin for 2 weeks followed by clarithromycin/rifampicin (RS2RC6) for 6 weeks in patients to determine the clinical and bacteriological effectiveness in a pilot study. Methods: Biopsies were obtained from infected human skin tissues and BALB/c mouse hind footpads before, during and after 8-weeks of rifampicin-containing combination antibiotic therapy. Lipids were extracted from tissues using organic solvents, mycolactone concentrations were measured using a cytotoxicity assay and mass spectrometry. Trends in mycolactone concentrations and clinical, bacteriological and immuno-histopathological responses were determined. Concentrations of cytokines in supernates of whole blood assays in humans or murine splenocytes after stimulation with mycobacterial antigens/T-cell mitogens were measured using ELISA. iv Results: Eighty-three patients with confirmed Buruli ulcer were randomized to RS8 or RS2RC6 and monitored for recurrence free-healing. Bacterial load in tissue samples before and after treatment for 6 and 12 weeks was monitored in samples obtained by 4mm punch biopsy by semi-quantitative culture. There was no difference in using RS8 or RS2RC6 with respect to healing rate or the proportion healed in each group after 4, 8, 12, 16, 20, 24 and up to 52 weeks. The success rate was 93% in each group and there was no recurrence after 12-month follow-up. There was no difference in the number of bacteria cultured at the different time points for the two regimens. Mycolactone was detectable in 92% and 77% of human samples (n=80) using cytotoxicity assays and mass spectrometry respectively. Antibiotic therapy was associated with a decline in tissue concentration of mycolactone in both human and murine-infected tissues which was paralleled by resolution of clinical lesions, reductions in bacteriological counts and restoration of local and systemic immune responses. Discussions/Conclusions: This study shows that mycolactone concentrations in tissues is closely associated with the presence of M. ulcerans and provides useful proof-of-concept data that mycolactone detection could potentially be used to monitor response to antibiotic therapy as well as for diagnosis of Buruli ulcer disease. The findings from the pilot study indicate that rifampicin combined with clarithromycin can replace rifampicin and streptomycin for the continuation phase after rifampicin-streptomycin treatment for 2 weeks without any apparent loss of efficacy. The implication is that a controlled trial of fully oral therapy using rifampicin and clarithromycin for 8 weeks (RC8) is justified.
- ItemLand use change, modelling of Soil Salinity and households’ decisions under Climate Change Scenarios in the Coastal Agricultural Area of Senegal(June, 2019) Thiam, Sophie; ; ;Soil salinity remains one of the most severe environmental problems in the coastal agricultural areas in Senegal. It reduces crop yields thereby endangering smallholder farmers’ livelihood. To support effective land management, especially in coastal areas where impacts of climate change have induced soil salinity and food insecurity, this study investigated the patterns and impacts of soil salinity in a coastal agricultural landscape by developing an Agent-Based Model (ABM) for Djilor District, Fatick Region, Senegal. Landsat images for 1984, 1994, 2007 and 2017 combined with normalised difference vegetation index (NDVI), elevation, wetness index and distance to the river were used to determine Land use-land cover and salinity changes. Land use classification and intensity analysis were applied to determine the time intervals during which the annual change area is relatively slow versus fast, and the variation of the categories’ gains and losses during a time interval. Soil samples plots (at 0-30 cm depth) were collected according to different land use, soil and crop types to determine the salinity patterns. Households’ survey data were collected based on 304 selected respondents to assess the perception and adaptation strategies of farmers. Land Use-Salinity Interaction (LUSI) was developed to explore the potential impacts of increased temperature and farmers’ decisions on soil salinity dynamics. Salt content, crop yield and households’ decisions sub models were incorporated in LUSI model. Three scenarios were simulated over a 20-year period, namely Baseline (current trend), 1 °C increase in temperature (Temp1) and 2 °C increase in temperature (Temp2). Eight LULC were identified in Djilor: mangrove, forests, savannah shrubs, croplands, bare lands, salt marshes, sabkha and water bodies. Forests and croplands constitute the major land use in terms of area. Croplands recorded the highest gain (17 %) throughout the period from 1984 and 2017, while forest registered the highest loss (12.5 %). The time interval 1984- 1994 had the fastest annual area change. Regarding soil salinity, bare lands, fallow lands, rice plots and Fluvisols registered high values in salt content. Clay content, elevation and distance to river were the important factors associated with the increased salt content. In 1984, highly saline and moderately saline areas were the largest in extent 32.65 % and 38.9 %, respectively. In 2017, slightly saline areas increased to 39.69 %, while highly saline and moderately saline areas decreased to 20.85 % and 25.60 %, respectively. Sabkha and salt marshes cover had the largest salt-affected areas over time. Regarding the social response to salt content, local perception of soil salinity indicates a general increase of soil salinity in the area. Women group engaged in rice farming appeared to be more affected by soil salinity. To cope with the negative impact of soil salinity, the farmers’ strategies are mainly the application of chemical fertilizer and manure, planting and conservation of trees, and installation of soil bunds. Simulation of soil salinity under current conditions showed an increasing trend of salinity over the next 20 years. The average EC was 6.48 dS/m and 9.77 dS/m for Temp1 and Temp2 scenarios, respectively for the period 2017-2036. Temp1 and Temp2 scenarios will contribute to increase the mean EC by 7.7 % and 15.8 % per year, respectively. Simulated salinity will also contribute to decrease crop yield. Rice crop registered the lowest yield over time with 228, 187, 149 kg ha-1 y-1 in BAS, Temp1 and Temp2, respectively, compared to maize, millet and groundnut. This study recommends the implementation of appropriate land management and mitigation strategies for preventing climate change and its effects on salinity dynamics in the coastal regions of Senegal by policy makers and other stakeholders.
- ItemLong -Term Vegetation Dynamics over the Bani River Basin as Impacted by Climate Change and Land Use(2015-07-29) Traore, Souleymane SidiThis study investigated the long-term trends in vegetation and rainfall and the extent and rate of vegetation change over the Bani river Basin at multiple spatial and temporal scales in relation to local and regional drivers. Monthly 8-km Normalized Difference Vegetation Index (NDVI) time-series data from 1982 to 2011 was derived from 10-day Satellite Pour l’Observation de la Terre vegetation product (SPOT-VGT) at 1-km (1998-2011) and 15-day GIMMS (Global Inventories Monitoring and Modelling Systems) at 8-km satellite data (1982-2006). Gridded rainfall data at 8-km grid resolution was created from 40 meteorological stations and complemented with Tropical Rainfall Measurement Mission (TRMM) data. A Mann Kendall (MK) trend analysis was used to determine the trend for each dataset using monthly and annual time-series. This analysis produced some indicators like Kendall’s tau, p-value and Theil-Sen. The p-value estimator (p-value less than 0.07) was used in this study to show the significance of the trend. Trend analysis revealed that within the study area vegetation greening trends are mostly associated with areas where natural vegetation is still well represented. From the results 934 pixels (49% of the study area) showed a positive trend while 155 pixels (8% of the study area) showed a negative trend significant at p-value less than 0.07. During the same period rainfall had increased by about 17 mm, translating into a positive trend for almost the entire study area. Vegetation productivity in the study area is dependent on rainfall which varies greatly temporally and spatially. The linear Pearson correlation was used to estimate the relationship between NDVI and rainfall for every pixel at monthly interval for the growing season data. Comparing their long-term mean the result showed a good correlation between the two datasets with an R value of 0.98. Four (4) reference areas were used to explain and cross verify representative areas that exhibit either entirely negative MK-trends or entirely positive MK-trends over the monitoring period. These reference areas were selected based on their trend in rainfall and NDVI and their NDVI long-term departure. Free 30-meter Landsat images were acquired for the four reference areas for the following three intervals: 1984 and 1986, 1999 and 2000 and 2009 and 2010. Land Use/Land Cover (LULC) change was then quantified and the rate of land conversion was determined. LULC variables included urban, Cropland and natural vegetation (Shrublands, Steppe, Open Trees and Closed Trees). For the entire period, the class ‘Natural Vegetation’ decreased between 22.83% and 63.47% from its initial area for areas (1) and (2), while the decrease was 8.35% for area (3) and 13.39% for area (4). The class ‘Cropland’ increased for 564.86% in area (3); 62.17% in area (4); 35.79% in area (2) and 16.22% in area (1). To investigate whether there is a relationship between NDVI, rainfall and LULC change, LULC variables were correlated with long-term trend in rainfall and NDVI. The results showed there is a positive correlation between increases in rainfall and some land cover classes, while some classes such as settlements were negatively correlated with vegetation productivity trends. Croplands and Natural Vegetation were positively correlated (r=0.89) with rainfall while settlements have a negative correlation with NDVI time series trends (r=-0.57). Despite the fact that rainfall is the major determinant of vegetation cover dynamics in the study area, it appears that other human-induced factors such as urbanisation have negatively influenced the change in vegetation cover. The results provide spatially explicit and temporally good and rich information of vegetation productivity dynamics and its drivers at landscape scale. This is an important input for assessing the impact of climate change on vegetation for biophysical modelling. It also improves our knowledge of the drivers of vegetation productivity changes. The study suggests that NDVI can be useful for general vegetation cover monitoring and planning. Future studies need to also look at the effect of vegetation cover change in regard to other landscape components such as specifically population density and soil degradation.
- ItemMechanistic Studies and Mathematical Models for Mycolactone Toxin and Autoinhibitory WASP: Model Mechanisms for Buruli ulcer Initiation and Spread.(2015-11-09) Nyarko, Peter RomeoThe Wiskott-Aldrich Syndrome Protein (WASP) has been implicated in many diseases such as Wiskott-Aldrich Syndrome (WAS) and Buruli ulcer. Mycobactrium ulcerans is the main causative organism of Buruli ulcer (BU) disease. The bacteria secretes a polyketide lipid toxin (Mycolactone). The toxin not only di uses through the cell membranes, but also binds, hijacks and disrupts the normal functions of WASP in the cytoplasm leading to over polymerization of actin lament, cytoskeletal rearrangement and eventually cell death through necrosis. In pre-ulcerative BU disease, toxins extend beyond the actual size of the lesion. A mathematical model is developed to describe the binding mechanism of the two conformations of WASP and the complexes formed using the idea of isomerization. The formulation utilizes ligand concentration-dependence (ligand-receptor), equilibrium and conservation principles. By this approach, we are able to determine the fractional response of WASP against change in concentration of its activators;