ghanaopendata/ghanaian-research-english huggingface dataset:
Simplifying the analysis of soil particle sizes. I. Test of the Sur and Kukal's modified hydrometer method

This study tests the validity of the Sur and Kukal modified hydrometer method for particle size analysis on eight Ghanaian soils of varying texture. The method assumes that hydrometer readings at any time could be predicted from an exponential equation provided that two important parameters are known: the 4.5-min hydrometer reading (R4.5) and the exponent (B). In a series of sedimentation experiments conducted on each soil in this study, 11 hydrometer readings were taken between 40 s and 8 h. Some of these data were used to determine the value of the parameters R4.5 and the exponent B. The B values for the light textured soils were within the range of 4.2 × 10 -3 to 9.7 × 10-3 and were comparatively lower than those for the heavy textured soils (1.0 × 10-2 to 1.5 × 10-2). In addition, the R4.5 values were much lower for the light textured soils than for the heavy textured soils. Using these parameter values in the Sur and Kukal's equation enabled the prediction of the hydrometer readings at different times during the sedimentation process. The predicted 8-h hydrometer reading also was used to calculate the percent clay. A comparison between the observed and predicted hydrometer readings was satisfactory. The predicted percent clay also agreed very well with that observed for all soils (R2 = 0.96). It is concluded that the Sur and Kukal method indeed simplifies the determination procedure and yields acceptable results for a wide range of Ghanaian soils.

Source: UG
SIMS U–Pb zircon dating and Re–Os isotopic analysis of the Hulu Cu–Ni deposit, eastern Tianshan, Central Asian Orogenic Belt, and its geological significance

Exploration of the Hulu Cu–Ni–Co sulfide deposit in Eastern Tianshan, Central Asian Orogenic Belt, has detected horizons of sulfide mineralization in pyroxenite and peridotite units. SIMS U–Pb zircon ages of the gabbro-hosting Cu–Ni–Co sulfide deposit indicate that the Hulu intrusion was emplaced at 282.3 ± 1.2 Ma (95% confidence level, MSWD = 3.30, n = 13). Osmium isotopic data suggest that the Hulu intrusion and associated Cu–Ni mineralization were derived from crustally-contaminated mantle melts. The intrusions clearly show island-arc geochemical signatures, such as negative Nb, Ta, Zr and Ti anomalies and enrichment in LILE. These geochemical tracers indicate that the Hulu mafic–ultramafic intrusions, along with the Cu–Ni deposit, formed as a result of subduction of oceanic crust in the Early Permian. The arc-related geodynamic setting of the Hulu Cu–Ni deposit is unusual for magmatic sulfide deposits. This new type of ore deposit offers an alternative perspective for Cu and Ni exploration.

Source: UG
Sims zircon U-Pb geochronology and Sr-Nd isotopes of Ni-Cu-bearing mafic-ultramafic intrusions in Eastern Tianshan and beishan in correlation with flood basalts in Tarim Basin (NW China): Constraints on a CA. 280 MA mantle plume

Zircon SIMS U-Pb dating of the Poshi, Hongshishan, Bijiashan, and Huangshan Ni-Cu-bearing and Xiangshan Ni-Cu-Ti-Fe-bearing mafic-ultramafic intrusions in the Eastern Tianshan and Beishan Rift yields a relatively restricted range of 278.6 Ma to 284.0 Ma. The histogram of compiled age data of basalts in the Tarim Basin and mafic-ultramafic intrusions in the Eastern Tianshan and Beishan Rift has a peak of 280 Ma, which probably represents the time of mantle plume activity. The basalts have lower εNd(t) values in the range of -9.2 ~ -1.7 and Mg# of &lt;50, and higher TiO2 contents (&gt;2 wt.%), indicating that they were generated directly from a peripheral zone of the mantle plume by low degree of melting. The mafic-ultramafic intrusions have higher εNd(t) of -1.3~11.2 and Mg# of 33~90, and lower TiO 2 &lt; 1.8 weight percent, suggesting that their parental magmas were produced from lithospheric mantle source by high degree of melting due to higher temperature of the mantle plume head. A possible mantle plume model beneath lithospheric mantle of the Tarim Basin, Tianshan and Beishan and its spatial framework is suggested.

Source: UG
Simulating impact of seasonal climatic variation on the response of maize (Zea mays L.) to inorganic fertilizer in sub-humid Ghana

Under low input subsistence farming systems, increased pressure on land use and decreased fallow periods have led to a decline in soil productivity. The soils in sub-humid region of Ghana are generally poor and require mineral fertilizer to increase crop productivity. This paper presents the use of Agricultural Production Systems sIMulator (APSIM) to simulate the long term influence of nitrogen (N) and phosphorus (P) on maize (Zea mays L.) yield in Sub-humid Ghana. The APSIM model was evaluated at two sites in Ejura, on a rainfed experiment carried out on maize in 2008 major and minor seasons, under various nitrogen and phosphorus rates. The model was able to reproduce the response of maize to water, N and P, and hence simulated maize grain yields with a coefficient of correlation (R2) of 0. 90 and 0. 88 for Obatanpa and Dorke cultivars, respectively. A 21-year long term simulation, with different rates of N and P mineral fertilizer application, revealed that moderate application of N (60 kg N ha-1) and 30 kg P ha-1 improves both the long term average and the minimum yearly guaranteed yield. Variability in grain yield increased with increasing application of N fertilizer in both seasons. Treatments with P fertilizer application shows a similar trend for the major season and reverse trend for the minor season, thereby suggesting an interactive effect with rainfall amounts and distribution. Application of 30 kg P ha-1 significantly increased the response to N. The response to mineral fertilizer (N and P) applications varied between seasons, suggesting the need to have a range of fertilizer recommendations to be applied based on seasonal weather forecast. © 2012 Springer Science+Business Media Dordrecht.

Source: UG
Simulating the Impact of the Global Economic Crisis and Policy Responses on Children in Ghana

Like many countries in sub-Saharan Africa, Ghana is experiencing the impact of the global crisis and the uncertain economic outlook. Indeed, as Ghana’s economy is among the most open in Africa, it is expected that the country has been and will continue to be severely affected by the crisis, although strong export prices of its main exports (gold and cocoa) may at least partially counteract the effects associated with the crisis. The main goal of this paper is to understand the potential impacts of the 2008/9 global crisis on different dimensions of child poverty (monetary, hunger, school participation, child labour and access to health services) in Ghana and to support the policy-maker in designing the most appropriate policy response to counteract the negative effects of the crisis. As timely data are not available, a combined macro-micro economic model to predict the impact of the global crisis on children was developed. Simulations suggest that the financial crisis would increase monetary poverty and hunger across all regions of Ghana, eroding many of the gains made over the past few years. Indeed, in comparison with the year preceding the crisis, instead of a reduction of four percentage points in child monetary poverty in 2011 predicted in the absence of crisis, the simulations indicate a 6.6 percentage point increase, with a continuous increasing pattern over the period of study. The global crisis is also predicted to severely deepen hunger among children, which is simulated to increase up to 6.6 percentage points in 2011 beginning with a sharp increase already in 2009. For both monetary poverty and hunger, the impact of the crisis differs across all regions, with the Eastern, Volta and Greater Accra regions predicted to be the most affected. Children’s participation in schooling and labour, as well as their access to health services, are forecast to be much less affected by the crisis, although it is found to reverse predicted increases in enrolment and health access (with substitution toward more modern types of health services) and forecasted reductions in child labour. Finally, alternative policy options have been simulated: a cash transfer programme targeted to poor children is found to be generally more effective in protecting children than food subsidies. Indeed, with a total budget equivalent to 1% of 2008 GDP, a cash transfer – equivalent to an individual annual amount of 19.8 Cedis – would cut the predicted increase in monetary poverty by over two percentage points in 2011. Although Ghana might be in a position to rapidly implement a cash transfer programme building on the existing Livelihood Empowerment against Poverty (LEAP) programme, other interventions (or mix of policies) might be more cost-effective in the short run. A combination of a universal or regionally targeted cash transfer programmes for children aged 0 to 5 years old, together with a school-feeding programme in poorer regions, might represent an effective way to intervene quickly to improve child well-being.

Source: UG
Simulation of groundwater flow in a crystalline rock aquifer system in Southern Ghana - An evaluation of the effects of increased groundwater abstraction on the aquifers using a transient groundwater flow model

Monitored groundwater level data, well logs, and aquifer data as well as the relevant surface hydrological data were used to conceptualise the hydrogeological system of the Densu Basin in Southern Ghana. The objective was to numerically derive the hydraulic conductivity field for better characterization of the aquifer system and for simulating the effects of increasing groundwater abstraction on the aquifer system in the basin. The hydraulic conductivity field has been generated in this study through model calibration. This study finds that hydraulic conductivity ranges between a low of 2m/d in the middle sections of the basin and about 40m/d in the south. Clear differences in the underlying geology have been indicated in the distribution of aquifer hydraulic conductivities. This is in consonance with the general assertion that the hydrogeological properties of the aquifers in the crystalline basement terrains are controlled by the degree of fracturing and/or weathering of the country rock. The transient model suggest aquifer specific storage values to range between 6.0×10-5m-1 and 2.1×10-4m-1 which are within acceptable range of values normally quoted for similar lithologies in the literature. There is an apparent subtle decrease in groundwater recharge from about 13% of the annual precipitation in 2005 to about 10.3% of the precipitation in 2008. The transient model was used to simulate responses of the system to annual increment of groundwater abstraction by 20% at the 2008 recharge rates for the period 2009 - 2024. The results suggest that the system will not be able to sustain this level of abstraction as it would lead to a basin wide drawdown in the hydraulic head by 4m by the end of the prediction period. It further suggests a safe annual increment in groundwater abstraction by 5% under business as usual recharge conditions. Identification and protection of groundwater recharge areas in the basin are recommended in order to safeguard the integrity of the resource under the scenario of increased abstraction for commercial activities in the basin. © 2012 John Wiley &amp; Sons, Ltd.

Source: UG
Simulation of the dry matter production and seed yield of common beans under varying soil water and salinity conditions

We present a model that simulates the effects of water and salinity stress on the growth of beans. The model derives a combined soil water/salinity stress factor from the total water potential (combination of the matric and the osmotic potentials) and uses this stress factor as a growth limiter in a growth model. The model was tested on data obtained from two greenhouse trials of beans (Phaseolus vulgaris) grown under a range of soil water and salinity conditions. The simulated dry weight of the bean generally followed those observed. In the first trial, the comparison between simulated and observed total dry weight and seed yield gave R2 values of 0.97 and 0.92, respectively. Comparison of the simulated to the observed dry weight for the second trial gave R2 values of 0.85 and 0.89, respectively. These indicate a good performance of the model in general. The principle of deriving a combined water/salinity stress from the matric and osmotic potentials is simple and can be included as a simple routine in many existing crop models without much difficulty. © 2001 Elsevier Science B.V.

Source: UG
Simulation of the Rainfall Regime over Ghana from CORDEX

This paper investigates how well the rainfall regime on which many livelihoods depend, in Ghana is well represented by the Coordinated Regional Climate Downscaling Experiment (CORDEX). The objective of the study is to demonstrate how well the ten CORDEX models are able to capture the spatial and temporal rainfall seasonality over the southern and northern sub-sections of Ghana. The choice of the sub-sections is based on the fact that south of 8˚N experiences a bi-modal rainfall regime while the north has a uni-modal regime. The results indicate that the rainfall over Ghana is associated with high levels of variability at the inter-annual time scale. Particularly over the southern part of Ghana, all the models follow the same trend as represented over Ghana with similar rainfall values as the observation. Over the northern part of Ghana, models record relatively low rainfall agreeing with the observation. However, most of the models overestimate the northern region rainfall as it is in the case of the southern Ghana. CORDEX as shown in this analysis could be useful in providing Ghana with at least 10 different model outputs for impact analysis. Caution is however given that, since individual models give different performance and the fact that models in general have their inherent deficiencies, an ensemble mean of the models could provide a better result.

Source: UG
Simulations of Policy Responses and Interventions to Promote Inclusive Adaptation to and Recovery from the COVID-19 Crisis in Ghana

We assess the impact of COVID-19 shocks on household welfare and the effectiveness of select policies implemented to reduce their impact on welfare in Ghana. We adopt a microsimulation approach to assess the effects of COVID-19 on household welfare. Welfare fell by 34.2% to 41.9% between March and June 2020. Over the same period, the poverty headcount and the Gini index increased by 9 to 10.5 percentage points and 0.4 to 0.6 points, respectively. The number of poor people increased by 2.8 to 3.2 million. The hardest-hit sector was education, followed by agriculture and forestry and fishing, trade and repairs, manufacturing, and other services also affected. The effects vary for men, women and children. While women experienced the largest decline in welfare, men experienced the highest increase in poverty incidence. The three policies selected reduced poverty marginally but were unable to offset the increase in poverty that occurred between March and June. The estimated cost of the three policies is GHS3.7 billion excluding administrative costs, which equates to approximately 1% of 2020 GDP

Source: UG
Simultaneous determination of tantalum, niobium, thorium and uranium in placer columbite-tantalite deposits from the Akim Oda District of Ghana by epithermal instrumental neutron activation analysis

Tantalum, niobium, thorium and uranium contents of 21 columbite-tantalite minerals from the Akim Oda District of Ghana have been determined using epithermal instrumental neutron activation analysis (ENAA) with a conventional counting system. As thermal neutron filters, boron carbide was encapsulated in the irradiation vials during irradiation. The samples were irradiated at one of the outer irradiation channels in the Ghana Research Reactor-1 facility, and counted directly. Various elements were identified and quantified using 172 keV of 182mTa, 871 keV of 94mNb, 86.5 keV of 233Th and 74.7 keV of 239U. The precision and accuracy of the method were evaluated using standard reference materials and the precision was found to be within 5% with comparable accuracy. The composition of columbite-tantalite minerals ranged from 33.1% to 59.2% Ta2O5 and 19.2% to 44.6% Nb2O5, ThO2 and U3O 8 the levels were 0.024-0.045% and 0.014-0.048%, respectively. © 2005 Akadémiai Kiadó.

Source: UG
Simultaneous quantile regression and determinants of under-five severe chronic malnutrition in Ghana

Background: Under-five malnutrition is a major public health issue contributing to mortality and morbidity, especially in developing countries like Ghana where the rates remain unacceptably high. Identification of critical risk factors of under-five malnutrition using appropriate and advanced statistical methods can help formulate appropriate health programmes and policies aimed at achieving the United Nations SDG Goal 2 target 2. This study attempts to develop a simultaneous quantile regression, an in-depth statistical model to identify critical risk factors of under-five severe chronic malnutrition (severe stunting). Methods: Based on the nationally representative data from the 2014 Ghana Demographic and Health Survey, height-for-age z-score (HAZ) was estimated. Multivariable simultaneous quantile regression modelling was employed to identify critical risk factors for severe stunting based on HAZ (a measure of chronic malnutrition in populations). Quantiles of HAZ with focus on severe stunting were modelled and the impact of the risk factors determined. Significant test of the difference between slopes at different selected quantiles of severe stunting and other quantiles were performed. A quantile regression plots of slopes were developed to visually examine the impact of the risk factors across these quantiles. Results: Data on a total of 2716 children were analysed out of which 144 (5.3%) were severely stunted. The models identified child level factors such as type of birth, sex, age, place of delivery and size at birth as significant risk factors of under-five severe stunting. Maternal and household level factors identified as significant predictors of under-five severe stunting were maternal age and education, maternal national health insurance status, household wealth status, and number of children under-five in households. Highly significant differences exist in the slopes between 0.1 and 0.9 quantiles. The quantile regression plots for the selected quantiles from 0.1 to 0.9 showed substantial differences in the impact of the covariates across the quantiles of HAZ considered. Conclusion: Critical risk factors that can aid formulation of child nutrition and health policies and interventions that will improve child nutritional outcomes and survival were identified. Modelling under-five severe stunting using multivariable simultaneous quantile regression models could be beneficial to addressing the under-five severe stunting.

Source: UG
Simultaneous targeted and non-targeted analysis of plastic-related contaminants in e-waste impacted soil in Agbogbloshie, Ghana

An LC-MS based analytical method was developed and validated for the simultaneous targeted analysis and suspect screening of plastic-related contaminants in e-waste impacted soils. Satisfactory recoveries (97 ± 13 %) were achieved using ultrasound-assisted extraction for 14/15 of the targeted analytes (7 bisphenols and 8 plasticizers) in a range of agricultural and non-agricultural soils. The method was applied to 53 soil samples collected in May 2015 in the region of Agbogbloshie (Ghana) at e-waste facilities (incl. Dump, trade, and burn sites), neighboring non-agricultural (incl. upstream, downstream, and community) and agricultural fields, and at two control agricultural sites away from e-waste recycling facilities. Bisphenol A (BPA) and bis(2-ethylhexyl) phthalate (DEHP) were the two dominant contaminants in e-waste soil (with concentrations up to 48.7 and 184 μg g− 1 , respectively), especially at the trade site, where e-waste was sorted and dismantled. The non-targeted workflow was successfully applied to identify additional plastic-related contaminants previously unreported in e waste impacted soils, including bis(2-propylheptyl) phthalate, diisononyl phthalate, trioctyl trimellitate, 4-dode cylbenzenesulfonic acid, perfluorooctanesulfonic acid, perfluorobutanesulfonic acid, diphenyl phosphate, and triethylene glycol monobutyl ether. The agricultural soils surrounding the e-waste sites were also contaminated by plastic-related chemicals (especially DEHP), highlighting the impact of e-waste activities on the surrounding agricultural system.

Source: UG
Simultaneous Targeted And Non-Targeted Analysis Of Plastic-Related Contaminants In E-Waste Impacted Soil In Agbogbloshie, Ghana

An LC-MS-based analytical method was developed and validated for simultaneous targeted analysis and suspect screening of plastic-related contaminants in e-waste-impacted soils. Satisfactory recoveries (97 ± 13 %) were achieved using ultrasound-assisted extraction for 14/15 of the targeted analytes (7 bisphenols and 8 plasticizers) in a range of agricultural and non-agricultural soils. The method was applied to 53 soil samples collected in May 2015 in the region of Agbogbloshie (Ghana) at e-waste facilities (incl. Dump, trade, and burn). sites), neighboring non-agricultural (incl. upstream, downstream, and community) and agricultural fields, and at two control agricultural sites away from e-waste recycling facilities. Bisphenol A (BPA) and bis(2-ethylhexyl) phthalate (DEHP) were the two dominant contaminants in e-waste soil (with concentrations up to 48.7 and 184 μg g− 1 respectively), especially at the trade site, where e-waste was sorted and dismantled. The non-targeted workflow was successfully applied to identify additional plastic-related contaminants previously unreported in e-waste-impacted soils, including bis(2-propylheptyl) phthalate, diisononyl phthalate, trioctyl trimellitate, 4-dodecylbenzenesulfonic acid, perfluorooctanesulfonic acid, perfluorobutanesulfonic acid, diphenyl phosphate, and triethylene glycol monobutyl ether. The agricultural soils surrounding the e-waste sites were also contaminated by plastic-related chemicals (especially DEHP), highlighting the impact of e-waste activities on the surrounding agricultural system.

Source: UG