926 research outputs found

    Land Use Land Cover Change within Kakum Conservation Area in the Assin South District of Ghana, 1991-2015

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    Kakum Conservation Area is roughly 1187km2, extending over large portions of forest reserves in the Assin South District of Ghana. The district hosts the remaining biodiversity hotspots within highly fragmented rainforest of West Africa. Although the conservation has been gazetted as protected area, it has since been impacted by illegal chainsaw logging, expanding agricultural land use and built construction to meet the housing needs of the rapidly growing population of the district. However, there is paucity of data on the magnitude, rate and types of land cover change occurring in the district. This study seeks to address these by examining the magnitude, the rate and direction of change in land cover between 1991 and 2015. The study objective was achieved using supervised classification and post classification change detection of remotely sensed Landsat satellite imagery of the district taken in 1991, 2001 and 2015. The results show that, within the study period, the population of the area increased by 2.9%, thick forest decreased by 8.2km2, light forest increased by 5.3km2 and built environment increased by 2.9km2 per annum. These results are considered potential hindrance to sustainable development, including biodiversity conservation in the forest reserves and climate change mitigation in general. There is therefore need for measures to end deforestation and stimulate reforestation of the lost forest cover. The district needs to initiate an enquiry into the effectiveness of the current forest reserve management practices and sustainability of land use systems in the district

    Re-Design of Mine Tailings Storage Facility for Adamus Resources Limited

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    AbstractThe suitability of a centerline or upstream design as a sustainable option for construction of future raises for the existing Life of Mine (LoM) downstream Tailings Storage Facility (TSF) at Adamus Resources Limited (ARL) was investigated using Slope/W in GeoStudio Software. Review of technical information, evaluation of the performance of the existing Stage 6 dam, and geotechnical investigations of available construction materials were undertaken in this research. Insights were gained about the TSF’s life cycle and current bearing capacity for intended future raises. Viable geotechnical parameters were established to define construction material specifications as well as input data for modelling the new designs. The British Standards Institute (BSI) standards were adopted for all the material testing protocols carried out at the Council for Scientific and Industrial Research-Building and Road Research Institute (CSIR-BRRI) laboratory in Kumasi. The scope of modelling covered the original downstream as well as the centerline and upstream options. The geometric design and stability analysis focused only on the southern and northern embankments of the TSF. The modelling outputs yielded reliable Stability Factors of Safety (FoS) for all designs investigated, above the regulatory criteria. Subsequently, a semi-quantitative multi-criteria evaluation was used to select the preferred option between the centreline and upstream alternatives. The results showed that technically, economically and by regulatory compliance, the centreline design is a better alternative and therefore recommended for adoption by ARL. Keywords: Tailings Storage Facility, Geotechnical Parameters, Stability Analysis, Modelling, Multi-Criteri

    Carbothermal Upgrading of the Awaso Bauxite Ore using Sawdust and Coconut Shells as Reductant

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    Ghana’s bauxite is exported in the raw state with no value addition. One way to achieve value addition is to carbothermally upgrade the ore into magnetic and nonmagnetic fractions, followed by separation using a magnet. This work investigates the carbothermal upgrading of the Awaso bauxite ore using reductant generated from locally available saw dust (SD) and coconut shells (CNS). Composite pellets of bauxite-reductant were prepared, air-dried and cured for 72 hours. The cured pellets were placed in a fire-clay crucible and heated in a custom-made gas-fired furnace for 30 minutes. The fired composite pellets were separated into magnetic and non-magnetic portions using a low intensity hand-held magnet. The various portions were then characterised using XRD, XRF and SEM analyses. XRD results showed magnetite as the predominant species present in the magnetic fraction whilst the non-magnetic fraction showed alumina as the predominant peaks along with some traces of unreduced hematite, silica, carbon and titania but no hercynite.  Keywords: Bauxite, Palm Nut Shells, Gas-Fired Furnace, Hercynite, Cha

    Effects of Harvest Time and Storage Form on Insect Population and Damage of Maize

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    The aim of this study was to determine the effects of harvest time and storage form on population levels of insect pests and their damage on stored maize. Maize was cultivated on a total land area of 19 x 23m2 during the major season (April to August 2020) and minor season (September to December 2020). Maize was harvested at three stages; early harvest, mid harvest and late harvest. Harvested maize was stored in three ways; husked, de-husked and shelled. Analysis of variance (ANOVA) was applied to the data through Sisvar version 5.6. Insect pests that were sampled during the study were Sitophilus zeamais, Cathartus quadricollis, Carpophilus dimidiatus and Tribolium castaneum. Carpophilus dimidiatus were sampled from treatments during the major season whereas Tribolium castaneum was sampled during the minor season. Sitophilus zeamais and Cathartus quadricollis were sampled in both seasons.  In the major season, late harvest shelled maize (LHS) recorded 689% more S. zeamais numbers as compared to early harvest husked maize (EHH). Mid-harvest husked maize (MHH) had 307% less number of S. zeamais compared to LHS in the minor season. Late-harvest shelled maize (LHS) had the highest percentage insect damaged kernels (86.94%) in the major season

    Agro-climatic and hydrological characterization of selected watersheds in northern Ghana

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    United States Agency for International Developmen

    Digyalipopeptide A, an antiparasitic cyclic peptide from the Ghanaian Bacillus sp. strain DE2B.

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    Acknowledgements We acknowledge the mass spectrometry data received from the laboratory of Professor Pieter C. Dorrestein and AndrĂ©s Mauricio Caraballo RodrĂ­gueze. Funding K.K., H.D and M.J. are grateful for the financial support of Leverhulme Trust-Royal Society Africa award (AA090088) and the jointly funded UK Medical Research Council–UK Department for International Development (MRC/DFID) Concordat Agreement African Research Leaders Award (MR/S00520X/1). A.P.N. is thankful for the award of a Ph.D. scholarship by the Organization for Women in Science for the Developing World (OWSD), the Swedish International Development Cooperation Agency (SIDA) and the Carnegie BANGA-Africa Project Award for a Ph.D. scholarship.Peer reviewedPublisher PD

    Podoconiosis in East and West Gojam Zones, Northern Ethiopia

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    Background: Podoconiosis is a neglected tropical disease (NTD) that is prevalent in red clay soil-covered highlands of tropical Africa, Central and South America, and northern India. It is estimated that up to one million cases exist in Ethiopia. This study aimed to estimate the prevalence of podoconiosis in East and West Gojam Zones of Amhara Region in northern Ethiopia. Methodology/Principal Findings: A cross-sectional household survey was conducted in Debre Eliyas and Dembecha woredas (districts) in East and West Gojam Zones, respectively. The survey covered all 17,553 households in 20 kebeles (administrative subunits) randomly selected from the two woredas. A detailed structured interview was conducted on 1,704 cases of podoconiosis identified in the survey. Results: The prevalence of podoconiosis in the population aged 15 years and above was found to be 3.3% (95% CI, 3.2% to 3.6%). 87% of cases were in the economically active age group (15–64 years). On average, patients sought treatment five years after the start of the leg swelling. Most subjects had second (42.7%) or third (36.1%) clinical stage disease, 97.9% had mossy lesions, and 53% had open wounds. On average, patients had five episodes of acute adenolymphangitis (ALA) per year and spent a total of 90 days per year with ALA. The median age of first use of shoes and socks were 22 and 23 years, respectively. More men than women owned more than one pair of shoes (61.1% vs. 50.5%; x2 = 11.6 p = 0.001). At the time of interview, 23.6% of the respondents were barefoot, of whom about two-thirds were women. Conclusions: This study showed high prevalence of podoconiosis and associated morbidities such as ALA, mossy lesions and open wounds in northern Ethiopia. Predominance of cases at early clinical stage of podoconiosis indicates the potential for reversing the swelling and calls for disease prevention interventions

    Integration of multiple geospatial applications and intelligence for responding to COVID-19 in Ghana

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    Objective: We describe the use of integrated geospatial applications for the provision of access to timely and accurate data on samples, visualisation of Spatio-temporal patterns of cases and effective communication between field sample collectors, testing laboratories, Regional Health directors and Government Decision Makers.Design: This study describes how an integrated geospatial platform based on case location and intelligence was developed and used for effective COVID-19 response during the initial stages of COVID-19 in Ghana.Data Source: Collector for ArcGIS, ArcGIS Survey123Main outcome measure: successful development and deployment of integrated geospatial applications and analytics.                                                              Results: The Collector for ArcGIS app was customised to collect COVID-19 positive cases location information. Survey 123 was introduced as a COVID-19 contact tracing application to digitise the case-based forms and provide real-time results from the laboratories to GHS and other stakeholders. The laboratory backend allowed the testing laboratories access to specific information about each patient (sample) collected by the fieldworkers. The regional supervisors’ backend web application provided accessing test results for confidentiality and timely communication of results.Conclusion: Geospatial platforms were successfully established in Ghana to provide timely results to Regional Health Directors and Government decision-makers. This helped to improve the timeliness of response and contact tracing at the district level

    A hierarchical Bayesian model for estimating age-specific COVID-19 infection fatality rates in developing countries

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    The COVID-19 infection fatality rate (IFR) is the proportion of individuals infected with SARS-CoV-2 who subsequently die. As COVID-19 disproportionately affects older individuals, age-specific IFR estimates are imperative to facilitate comparisons of the impact of COVID-19 between locations and prioritize distribution of scare resources. However, there lacks a coherent method to synthesize available data to create estimates of IFR and seroprevalence that vary continuously with age and adequately reflect uncertainties inherent in the underlying data. In this paper we introduce a novel Bayesian hierarchical model to estimate IFR as a continuous function of age that acknowledges heterogeneity in population age structure across locations and accounts for uncertainty in the estimates due to seroprevalence sampling variability and the imperfect serology test assays. Our approach simultaneously models test assay characteristic, serology, and death data, where the serology and death data are often available only for binned age groups. Information is shared across locations through hierarchical modeling to improve estimation of the parameters with limited data. Modeling data from 26 developing country locations during the first year of the COVID-19 pandemic, we found seroprevalence did not change dramatically with age, and the IFR at age 60 was above the high-income country benchmark for most locations

    Repellency Potential, Chemical Constituents of Ocimum Plant Essential Oils, and Their Headspace Volatiles against Anopheles gambiae s. s., Malaria Vector

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    African malaria mosquitoes (Anopheles gambiae sensu stricto) transmit a malaria parasite (Plasmodium falciparum) to humans. The current control strategies for the vector have mainly focussed on synthetic products, which negatively impact the environment and human health. Given the potential use of environmentally friendly plant-derived volatiles as a control, this work aims to examine and compare the repellency potential of essential oils and headspace volatiles from Ocimum gratissimum, Ocimum tenuiflorum, and Ocimum basilicum and their chemical compositions. The repellency potential and chemical composition of the plants were achieved by using the protected arm-in-cage method and gas chromatography-mass spectrometry (GC-MS) analysis. Among the three Ocimum species, both the essential oils and the headspace volatiles from O. tenuiflorum achieved the longest repellency time lengths of 90–120 minutes. One hundred and one (101) chemical constituents were identified in the headspace volatiles of the three Ocimum spp. Nonetheless, (−)-camphor, (E)-Îł-bisabolene, terpinolene, ÎČ-chamigrene, cubedol, (E)-farnesol, germacrene D-4-ol, viridiflorol, Îł-eudesmol, tetracyclo [6.3.2.0 (2,5).0(1,8)] tridecan-9-ol, 4,4-dimethyl, α-eudesmol, isolongifolol, and endo-borneol were unique only to O. tenuiflorum headspace volatiles. Either essential oils or headspace volatiles from O. tenuiflorum could offer longer protection time length to humans against An. gambiae. Though field studies are needed to assess the complementarity between the chemical constituents in the headspace volatiles of O. tenuiflorum, our observations provide a foundation for developing effective repellents against An. gambiae
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