470 research outputs found

    A simple method for the extension of shelf life of cultures of Phytophthora species causing black pod disease of cacao (Theobroma cacao L.)

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    Black pod disease of cacao caused by Phytophthora palmivora and Phytophthora megakarya in Ghana take heavy toll of cacao production in the field. Intensive research has been carried out worldwide on these pathogens. However, viability of the cultures during prolonged storage has remained a major challenge in the research. This paper reports findings of assessment of six storage media viz sterilised distilled water (SDW), sterilised and unsterilized soil suspension (SSS and USS), vegetable 8 juice broth (V8JB), Oat Meal Agar slant under mineral oil (at 4°C) and empty tube. Viability of the cultures was assessed on V8JA and in tetrazolium chloride test. Ability of zoospores of the cultures to infect cacao leaf discs was used to assess growth vigour and pathogenicity. Phytophthora cultures stored in SDW (26 ± 2°C; alternating day light and night) were preserved for 60 days (5 years). Both P. palmivora and P. megakarya performed better on SDW and SSS than on USS due to removal of staling substances in the soil medium by the sterilisation. Vigour of growth and pathogenicity of the stored cultures required re-inoculation of host tissue (cacao pod) in order to maintain potency to continually infect host

    Product Marking and Conformity Assessment of Portland Cements on the Ghanaian Market

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    Cement bound concrete materials and complementary fittings are requisite ingredients for all civil engineering works. In all these, Portland cement, a basic binding ingredient for the concrete work is the dominant binder. In Ghana, there are various brands of cement on the market. Five major brand products currently in circulation include the Ghana Cement (GHACEM), Western DIAMOND Cement (DIAMOND), CIMAF Cement, DANGOTE Cement and SUPACEM Cement. Increased infrastructural development has placed high demand on cement consumption. Consequently, new products keep emerging in the market. Indeed, a standard measure to provide product marking and evaluations of conformity to standard Class thresholds are required for the desired specification, properties and the performance quality of the cement products. This research therefore sets to ascertain the strength quality of the five cement brands on the Ghanaian market by checking their conformity to C-30 and C-40 standard compressive tests, using their 32.5-R and 42.5-R flagship brands. To achieve this, concrete cubes were moulded with fixed mix ratio of 1:1â…Ÿ2:3 and 1:1:2 for C-30 and C-40 respectively. To achieve the desired strength conformity, the slump as well as the coarse and fine aggregate constituents were standardised. The results indicated that the cement brands despite parading same strength thresholds in the market, do not exhibit same strength build-up. There are significant variations in growth of compressive strength over time. It was observed also that conformance threshold within 28 days was not attained for a number of the brands. Indeed, not until 56 days or more some of the brands could not achieve their desired compressive strength thresholds

    African rainforests: past, present and future

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    In recent decades, there has been a surge of interest in tropical forests, as there is increased appreciation of the rich biodiversity they host and the many roles they play in the functioning of the Earth system at local, regional and global scales. Of the world’s major tropical forest regions, most research and policy attention has focused on the Amazon region, the world’s largest tropical forest bloc, and to a lesser extent on South East Asia, the third largest tropical forest region. By contrast, the world’s second largest tropical forest region, the tropical forests of Central and West Africa (termed the Guineo-Congolian region) have been relatively neglected. This has been for a number of reasons, including challenging and fragmented politics, civil conflicts and logistical as well as infrastructure challenges. Nevertheless, there is an extensive amount of research activity in the African rainforest zone that has rarely been compiled in a single interdisciplinary volume. This review paper synthesizes the insights emerging from the theme issue on ‘African rainforests: past, present and future’ of Philosophical Transactions of the Royal Society.JRC.H.5-Land Resources Managemen

    The past, present and future of Africa's rainforests

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    The Africanwet tropics contain the second largest area of tropical rainforest in the world (second only toAmazonia), accounting for roughly 30% of global rainforest cover, the lush green heart of an otherwise generally dry continent. These rainforests have global significance and value as reservoirs of biodiversity, as stores and sinks of atmospheric carbon, as regulators of flow of mighty rivers, as sources of moisture to the atmosphere and engines of the global atmospheric circulation, as a key component of the Earth system and its biogeochemical cycles, and as providers of resources and ecosystem services to local communities and the region’s nations. They also have a unique and particular history of changes in climate and human pressure, and face a range of contemporary pressures. Over the twenty-first century, the African rainforest realmhas the potential to witness massive change, both through an expansion of deforestation, hunting and logging, and through the effects of global climate change. This Theme Issue presents a multidisciplinary perspective on the nature and ecology of the African rainforest biome, and examines the current pressures and future threats to this biome. Compared with the other major rainforest regions, Amazonia and Southeast Asia, the African rainforest realm remains understudied, and in particular there have been very few attempts at interdisciplinary synthesis. This Theme Issue is an attempt to address this deficit, and explores what we know about the African rainforests and the threats they face, and what we need to know is this century of rapid change. In some ways, this can be viewed as a complement to similar Theme Issues of this journal focused on the rainforests of Amazonia [1,2] and Southeast Asia [3].JRC.H.5-Land Resources Managemen

    Resilience to climate shocks in the tropics

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    This focus collection on resilience to climate shocks in the tropics draws together 16 papers that predominantly examine the impacts of, and responses to, the 2015/2016 El Niño-Southern Oscillation event, in a range of contexts. This introductory synthesis contextualises the collection of papers by reviewing important concepts and highlighting some important insights that emerge from the collection. The papers in this collection collectively highlight: the value of longitudinal and interdisciplinary research in understanding both the roots of, and responses to, resilience challenges; the critical interaction between climatic and land-use changes; and the ways in which governance arrangements underpin societal decision-making across a range of scales and contexts to shape resilience

    Indications for and the diagnostic yield of 24-hour Holter monitoring: a prospective study at the Korle Bu Teaching Hospital

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    Background: Holter monitoring (HM) is an important tool used to evaluate symptoms suspected to be caused by arrhythmias. This study was aimed at determining the diagnostic yield of Holter monitoring among symptomatic and asymptomatic patients undergoing HM at the Korle-Bu Teaching Hospital.Methods: This was a prospective study among 400 consecutive symptomatic and asymptomatic patients undergoing HM from August 2006 to December, 2009 at the Korle-Bu Teaching Hospital. Data from the Holter study were analyzed, and symptoms linked to arrhythmias were evaluated to determine the diagnostic yield of HM in symptomatic and asymptomatic patients. Results: The mean age of the patients was 51.81 ± 16 years. The most common indications (symptoms) for HM were palpitation (62.9%) and dizziness (34.0%); about half (53.3%) of the symptomatic patients had only one indication. Among the symptomatic group, 28 in 115 symptoms were linked to arrhythmias giving a diagnostic yield of 24.3% whereas in the asymptomatic group 1 in 33 of symptom was linked to arrhythmia giving a diagnostic yield of 3.0%. The study found an overall diagnostic yield of 19.6%.Conclusion: HM as a regular health check for the general population (asymptomatic cohorts) is not cost effective and does not provide significant data to influence care except when the subject is found to have symptoms.Funding: Funded by the AuthorsKeywords: arrhythmias, indications, Holter monitoring, diagnostic yield, Ghan

    Financial sector reforms and bank performance in Ghana

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    study evaluating NPART\u27s efficacy and providing figures on its implementatio

    Callus induction and plant regeneration via leaf segments of three accessions of African rice (Oryza glaberrimaStued.)

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    A study conducted with the aim of developing a protocol for callus induction and plantlet regeneration in vitro from leaf segments of three accessions of African rice (O. glaberrimaSteud.) indigenous to Ghana. Leaf segments of the accessions namely, Guame, N/4 and SARI 1 were assessed for callus induction and plantlet regeneration ability on different concentrations of plant growth regulators, incorporated into Murashige and Skoog, (1962) (MS) basal medium. Frequency of callus induction which was achieved on MS medium supplemented with (0-10) mg/l 2,4-D differed significantly (p≤0.05) among the accessions, as well as among the levels of 2,4-dichlorophenoxyacetic acid (2,4-D) tested. Highest callus induction frequency was exhibited at a concentration of 6 mg/l 2,4-D for all three accessions.Sub-culturing of callus on regeneration medium, which consisted of MS supplemented with (1:0-5) mg/l NAA:BAP resulted in no plantlet regeneration in all tested accessions. Instead, prolific root formation was observed

    A Survey of the Benthic Macrofauna and Fish Species Assemblages in a Mangrove Habitat in Ghana

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    In order to enhance ecological knowledge for coastal and mangrove  ecosystem conservation in Ghana, the study documents the taxonomic groups of benthic macrofauna and fish assemblages in an urban mangrove swamp as its fundamental objective with emphasis on their composition, richness and diversity. This is because benthic and fish fauna of mangrove habitats are amongst the least studied biota in Ghana. Fish and benthos sampling was undertaken from five randomly selected pools within a mangrove stand during the wet and dry seasons using pole-seine net (7 m long and 1.5 m depth, with stretched mesh size of 5 mm) and an Ekman grab (15 cm × 15 cm dimensions), respectively. All samples were  preserved in 10% formalin for laboratory analysis. The results indicated a more diverse macrozoobenthic community in the wet (H¹ = 1.8) than dry season (H¹ = 1.5) . Overall, five out of a total of 13 genera found are intolerant to pollution and four moderately tolerant, while four comprising polychaetes and the midge Chironomus, are pollution tolerant. This suggests that the mangrove habitat is less polluted. A grand total of 917 fish specimens, belonging to 15 species and nine families, were encountered for both seasons (371 and 546 specimens for wet and dry seasons, respectively). The black-chinned tilapia, Sarotherodon  melanotheron, was the dominant fish species in the wet season, accounting for 54.2% of the total fish caught, whilst the grey mullets, Mugil babanensis and Mugil curema, were the dominant species in the dry season, with a combined total of 51.4% of the fish population. However, over 70% of these dominant fish species from both seasons were juveniles providing a strong justification for the observation that the mangrove habitats are nursery grounds for fish inhabiting adjacent riverine, estuarine and inshore marine habitats. Considering this relevance of mangroves and the ongoing conversion attempts of mangrove habitats to other land uses, a concerted mangroves conservation effort is strongly advocated

    Food consumption pattern and dietary diversity of a vegetarian population in Ghana

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    Objective: This study examined the food consumption pattern and dietary diversity of a vegetarian population in the Greater Accra Region of Ghana.Methods: A cross-sectional study was employed to examine the nutritional status of four (4) vegetarian groups in the Greater Accra Region of Ghana. One hundred and twenty-two (122) vegetarians were recruited using the total enumeration technique. Food consumption pattern and dietary diversity were assessed using a validated qualitative food frequency questionnaire and a 24-hour dietary recall, respectively. Dietary diversity was calculated using the FAO guidelines.Results: Sixty eight percent (68%) of the vegetarians reported daily intakes of vegetable protein. Majority of the vegetarians (80.6%) reported daily intakes of cereals and grains while 54% reported daily intakes of tubers. Eighty two percent (82%) and 72% of the vegetarians consumed vegetables and fruits on daily basis respectively. A few ofthe vegetarians (29%) reported daily intakes of fruit juices. Soft drinks, deep fried foods and fast foods were occasionally consumed. About 40.3% of the vegetarians obtained a dietary diversity score of four (4). Majority of them (68.9%) had low dietary diversity.Conclusion: The vegetarians had low dietary diversity which may lead to inadequate nutrient intakes. Thus, there is the need for nutrition-related professionals to give appropriate information on a vegetarian diet and educate vegetarians to include a variety of foods in their diet
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