Mesozoic detrital zircon provenance of Central Africa: implications for Jurassic-Cretaceous tectonics, paleogeography and landscape evolution

Jurassic-Cretaceous tectonics, paleogeography and sedimentary provenance of central Africa are poorly constrained and continue to be debated. The lack of constraints on the timing and controls on late Mesozoic sedimentary basin development, drainage evolution and paleoenvironments is problematic because central Africa is well endowed with natural resources, and good understanding of these issues is fundamental to a better assessment of hydrocarbon and alluvial diamond exploration targeting. Moreover, by improving our understanding of Mesozoic strata across this vast region, we can also help to contextualise the ecological and evolutionary relationships of floras and faunas from central Africa with contemporary floras and faunas from different parts of Africa and throughout Gondwana. In particular, refining the depositional age of late Mesozoic units is key to understanding and reconstructing regional paleogeography and drainage patterns during this poorly resolved time period in Africa, which also furthers our understanding of the origins and dispersal pathways for Mesozoic, Cenozoic and modern African floras and faunas, as well as economically significant alluvial mineral resources, such as diamonds, that are important to the economies of this part of the world. To address these issues a detailed and multifaceted sedimentary provenance analysis of 14 late Mesozoic units from seven sedimentary basins across central Africa (spanning seven different countries) was conducted. This integrated sedimentological approach incorporated sandstone petrography, paleocurrent analysis, U-Pb detrital zircon geochronology, Lu-Hf isotope and trace element geochemistry to investigate Jurassic and Cretaceous continental deposits from central Africa. The main objective was to investigate late Mesozoic sedimentary basin development, drainage evolution and provide constraints on the age of deposition, sediment source and paleofluvial drainage patterns, using core and outcrop samples from across the region; including Democratic Republic of Congo (DRC), Kenya, Angola, Sudan, Tanzania, Zimbabwe and Malawi. Sandstone petrography and paleocurrent data indicate mixed sediment sources mainly to the south of study areas. Maximum depositional age analyses performed on U-Pb detrital zircon sample results demonstrate that most of the late Mesozoic units in central Africa are younger than previously accepted. Detrital zircon provenance analysis points to primary contributions from Neoproterozoic Pan-African Mobile Belts (e.g., Mozambique and Zambezi belts), which were probably exposed at this time are the dominant (>75%). The Lu-Hf isotope geochemistry results also show a mixed sediment provenance consisting of juvenile mantle and reworked crustal sources, which corroborates the sandstone petrography results. Western areas of central Africa (e.g. DRC and Angola) are dominated by sediments from reworked crustal sources, whereas eastern parts of central Africa (e.g. Sudan, Kenya and Tanzania) are dominated by sediments of juvenile mantle sources. The results further suggest a pattern of large ephemeral lakes in the Middle Jurassic to Early Cretaceous in the Congo and Zambezi basins, followed by the development of a large, dominantly north directed fluvial systems across central Africa in the middle Cretaceous. The results are supportive of a uniform northward continental drainage pattern throughout late Mesozoic, which supports the assertion that the paleo-Congo drainage system was likely north flowing, rather than east flowing out of the Congo Basin and into Indian Ocean as previously suggested. The results of this thesis are also supportive of the hypothesis of a major drainage divide between southern and central Africa during the late Mesozoic and the concept of a major NW trending fluvial drainage pattern into the shear zones within the Central African Rift System, although the ultimate depocentre still remains uncertain. The maximum depositional age of three Cretaceous sedimentary units, including the dinosaur-bearing Wadi Milk Formation of Sudan has been constrained. The new ages shows a generally much younger age of deposition than previous assignations, calling into question the reliability of these overly broad biostratigraphic age for these important sedimentary units

Does religion matter for earnings management?

This paper explores the nexus between earnings management and religiosity. It complements prior research on the impact of religious social norms of the firm’s environment on earnings management practices. Using a sample of 11,105 U.S. firm-year observations between 2004 and 2013, we find that religiosity is negatively associated with the accruals-based method, but positively related to both real-activities and classification shifting. This suggests that religiosity could serve as a correction mechanism to accruals earnings management practices. However, managers in highly religious areas consider real- activities and classification shifting as ethically and morally appropriate. In addition, we interact religiosity measures with governance variables to provide evidence of the importance of religion in relation to board characteristics. As part of robustness analysis we examine the impact of religion in high and low religious areas, as well as in urban and rural areas. Our findings remain robust and argue in favour of the importance of religious social norms in earnings management

Inoculum Concentration of Armillaria mellea in the Rhizosphere of Intercropped Teak Plantation: the case of the Opro Forest Reserve, Ghana

Teak (Tectona grandis Linn. F.) is the most planted timber tree species in Ghana, with over 73,916 hectares of plantation established at the end of 2008. Many of the teak plantations established in the semi-deciduous forest zones were done using the taungya system with various intercrops. Symptoms of Armillaria (Vahl: Fr.) root-rot of teak have been reported in the taungya plantations, especially in the semi-deciduous forest zones. The study aimed to determine inoculum concentrations of Armillaria mellea in the rhizosphere soil of intercropped teak and compare with sole teak plantation. Mycoflora were isolated from rhizosphere soil of teak intercropped with pepper, okra, maize, yam or cassava at year one to year three sapling stage. Dilution plate technique was used for mycoflora isolation and dilution factor of 10-3 was inoculated on potato dextrose agar amended with chloramphenicol (25mg/l) and incubated at 280C for 14 days after which A. mellea colonies were identified and counted. More A. mellea (Vahl: Fr.) colonies were isolated from rhizosphere soils of intercropped teak plantations than non-intercropped. Differences in A. mellea colonies were more significant amongst intercrops than amongst age of teak plantation at (P ≤ 0.05). There were significantly (P ≤ 0.05) higher numbers of A. mellea colonies in rhizosphere soils of teak intercropped with cassava compared with other intercrops. Number of A. mellea colonies in rhizosphere soils of intercropped teak did not have linear relation with age of teak plantation. Intercropping could promote Armillaria root rot of teak especially with cassava as intercrop

Optimisation of Operational Parameters of a Spiral Classifier Using Design of Experiment (DOE)

Abstract Classifying Mn Ore to improve upon the grade and the properties has become a crucial activity for the Mn industry since it increases the market value of the ore. Ghana Manganese Company (GMC) has renovated their oxide washing plant by integrating it with a spiral classifier to make a batch system operating process. Particle size of <3.35mm (Mn grade of 43-47%) obtained from the primary section of the plant served as feed to the classifier and with the plant condition (i.e. at 60 min washing time, 30 rev/min speed of spirals and feed tonnage of 6 t), Mn grade of 49% was achieved. This paper focused on the optimisation of some selected operational parameters of the classifier to obtain a Mn grade >50% using Design of Experiment (DOE). Series of test works were designed using the DOE for the classifier using the constraints of washing time (30-90 min), speed of spirals (20-40 rev/min) and feed tonnage (6-9 t). The outcome of the test work after simulation showed that all the selected parameters had a great influence on Mn grade. The spiral speed and feed tonnage correlated negatively to the Mn grade with washing time correlating positively. Operating the spiral classifier at a feed rate, spiral speed and washing time of 6 t, 25 rev/min, and 30 min, respectively, yielded Mn grade of 53%. A Confirmatory test using the established conditions gave a Mn grade of 53%, which is a 4% increment in the previous Mn grade which was 47%. The outcome of the studies is the new established operational conditions which is adhered to by the plant, producing a manganese concentrate grade ranging between 52-54%.   Keywords: Design of Experiment (DOE), Spiral Classifier, Grade, Manganes

THE IMPACT OF COVID-19 ON LEARNING - THE PERSPECTIVE OF THE GHANAIAN STUDENT

This study aimed at accessing the impact of Covid-19 on Ghana’s teaching and learning. The study employed a Descriptive survey design in which 11 items Likert-scale type of questionnaires was administered to 214 respondents mainly students in the second cycle and tertiary institutions of Ghana. The study employed simple random sampling technique in selecting the respondents for the study. The study revealed some challenges students encounter in the close down of schools due to the outbreak of the pandemic Covid-19: Students are unable to study effectively from the house thus, making the online system of learning very ineffective. Again, parents are incapable of assisting their wards on how to access online learning platform, neither can they entirely supervise the learning of their children at home without any complications. It came to light that the pandemic really has had a negative impact on their learning as many of them are not used to effectively learn by themselves. The e-learning platforms rolled out also poses challenge to majority of the students because of the limited access to internet and lack of the technical knowhow of these technological devices by most Ghanaian students. The study therefore recommends that students should be introduced to e-learning platforms to supplement classroom teaching and learning.  Article visualizations

Aboveground Biomass and Carbon content of a cocoa –Gliricida sepium agroforestry system in Ghana

To help overcome the challenge faced in re-establishing cocoa in degraded lands, some agroforestry trials were established with exotic leguminous tree species to determine their suitability for cocoa cultivation. However, our understanding of biomass accumulation and carbon sequestration in such specific agroforestry practices is still limited. In this study, the above-ground biomass and carbon storage and partitioning in a gliricidia-cocoa agroforestry system was investigated. Above-ground biomass accumulation and carbon stock varied significantly between the components of the system, with the gliricidia shade trees having the highest values and the cocoa trees having the lowest. The inclusion of the gliricidia shade trees in the system increased above-ground biomass and carbon capture of the system by some 60%, a greater proportion of which was contained in the branches of the shade trees. This pattern of dry matter distribution makes the species appropriate for use as a biomass producing species in agroforestry systems and demonstrates the potential of cocoa agroforestry systems for capturing and storing more atmospheric carbon than sole cocoa systems

Built-operate-transfer (BOT) model for public universities in Ghana for accelerating infrastructural development

Abstract: At independence, many countries look to reform education to accelerate economic and social development. Ghana is no exception, and after independence government saw in education the keys to social and economic development. Quality and availability of school infrastructure is one of the numerous problems confronting Ghana's education delivery. The purpose of this research is to find out infrastructure delivered by the private sector in our state Universities. The main objectives of this study were to assess the effectiveness of public private partnership in infrastructure development at the state public universities in Ghana, and also find out the number of infrastructure undertaken by the private sector; and to find out which of the PPP model is appropriate for the development of infrastructure in the state public universities. Data will be collected using the Delphi and field questionnaire survey. The Structural Equation Modeling (SEM) and Nvivo will be used to analyze data from the field questionnaire survey and Delphi respectively. This is a preliminary survey study on an ongoing Ph.D. study

Community perceptions of a malaria vaccine in the Kintampo districts of Ghana.

BACKGROUND: Malaria remains the leading cause of morbidity and mortality in sub-Saharan Africa despite tools currently available for its control. Making malaria vaccine available for routine use will be a major hallmark, but its acceptance by community members and health professionals within the health system could pose considerable challenge as has been found with the introduction of polio vaccinations in parts of West Africa. Some of these challenges may not be expected since decisions people make are many a time driven by a complex myriad of perceptions. This paper reports knowledge and perceptions of community members in the Kintampo area of Ghana where malaria vaccine trials have been ongoing as part of the drive for the first-ever licensed malaria vaccine in the near future. METHODS: Both qualitative and quantitative methods were used in the data collection processes. Women and men whose children were or were not involved in the malaria vaccine trial were invited to participate in focus group discussions (FGDs). Respondents, made up of heads of religious groupings in the study area, health care providers, traditional healers and traditional birth attendants, were also invited to participate in in-depth interviews (IDIs). A cross-sectional survey was conducted in communities where the malaria vaccine trial (Mal 047RTS,S) was carried out. In total, 12 FGDs, 15 IDIs and 466 household head interviews were conducted. RESULTS: Knowledge about vaccines was widespread among participants. Respondents would like their children to be vaccinated against all childhood illnesses including malaria. Knowledge of the long existing routine vaccines was relatively high among respondents compared to hepatitis B and Haemophilus influenza type B vaccines that were introduced more recently in 2002. There was no clear religious belief or sociocultural practice that will serve as a possible barrier to the acceptance of a malaria vaccine. CONCLUSION: With the assumption that a malaria vaccine will be as efficacious as other EPI vaccines, community members in Central Ghana will accept and prefer malaria vaccine to malaria drugs as a malaria control tool. Beliefs and cultural practices as barriers to the acceptance of malaria vaccine were virtually unknown in the communities surveyed

Determining Acid and Metalliferous Drainage Potential of Waste Rock on a Mine

Acid and Metalliferous Drainage (AMD) is recognised as serious environmental problem in the mining industry. This is because environmental issue of AMD poses serious threat to water quality, vegetation cover and social licence of the mining operations. AMD occurs when reactive sulphide bearing materials are exposed to oxidising conditions. It has now become imperative for some mining companies to test sulphide bearing minerals for their AMD potential before major mining excavations are done. This work determines the AMD potential of fifty (50) waste rock samples from a Mine using Acid Base Accounting (ABA) techniques. Mineralogical studies on the sample indicated that the major sulphide mineral assemblages present were pyrite, arsenopyrite and chalcopyrite. Paste pH showed that 20% of the samples had undergone weathering and as such AMD generation had already started. Approximately 22% of the sample had conductivity levels between 1000 to 10,000 µS/cm and this shows a typical AMD chemical characteristic of high salinity. Acid Base Accounting showed that 32% of the samples were acid generating. Exactly 16% were non-acid forming and 52% were uncertain. The analysis showed that the potential for AMD generation exists for the waste rock material and can affect the local environment, specifically water quality if preventive measures are not taken.   Keywords: Sulphide, Waste Rock, Acid Base Accounting, Paste pH, Conductivit

Effect of Cleopatra mandarin rootstock age on bud ‘take’ of Late Valencia sweet orange

Cleopatra mandarin is preferred to rough lemon as rootstock material for budding because of the susceptibility of the latter to major citrus diseases such as gummosis and phytophtora infections. However, Cleopatra mandarin rootstocks have poor bud ‘take’. The experiment was conducted at CSIR-Plant Genetic Resources Research Institute, Bunso to determine the effect of Cleopatra mandarin rootstock age on bud ‘take’ of Late Valencia sweet orange variety. Cleopatra mandarin rootstocks of ages 9 months, 10 months, 11 months and 12 months were budded with Late Valencia sweet orange variety using the chip budding technique in a randomised complete block design. There were 25 budded seedlings for each age group and replicated four times. Results obtained indicated that younger Cleopatra mandarin rootstock favoured bud ‘take’more than older ones. Higher bud ‘take’ was recorded in the 9-month old rootstocks followed by the 10-month old ones. Bud ‘take’, however, decreased with age of the rootstock. Differences in bud ‘take’between younger rootstocks (9 and 10 months old) were insignificant. There were, however, significant differences between bud‘take’ of younger rootstocks and older rootstocks (11 and 12 months old)