ghanaopendata/ghanaian-research-english huggingface dataset:
Extracts of Euphobia hirta linn and physalis angulata L. and their amalgamation demonstrate potency against Staphylococcus aureus and pseudomonas aeruginosa

PEG-ointmentObjective: The goal was to investigate the antibacterial activity of the extracts of Euphobia hirta and Pysalis angulata from Ghana on clinical bacteria isolate found to associate with wound and skin infections. Methods: The aqueous and crude ethanolic extracts and extract-PEG ointment formulation as well as the combination of the extracts of P. angulata and E. hirta were tested against Psedomonas aeruginosa and Staphylococcus. aureus, using the agar diffusion bioassay. Antibacterial activities were indicated by the diameters of zones of inhibition of bacterial growth for both the test extracts as well the extract-PEG ointment formulations. Results: Ethanolic crude extract of E. hirta inhibited P. aeruginosa at inhibition zones ranging from 24±0.08 mm at 50 μg/ml to 21.00±0.40 mm at 250 μg/ml, whilst the aqueous crude extracts showed potency against P. aeruginosa at varying inhibition zones ranging from 20±0.60 mm at 250 μg/ml to 4.00±0.20 mm at 50 μg/ml. Ethanolic E. hirta crude extracts exhibited potency against S. aureus and was dose dependent, with a decrease in inhibition as concentration increased, recording a minimum zone of inhibition at 13.00±0.30 mm at 250 μg/ml and maximum zone of inhibition of 16.00±0.20 mm at 50 μg/ml. Only one concentration of 100 μg/ml at 20±0.60 mm zone for the aqueous extract of E. hirta was potent against S. aureus. Ethanolic crude extract of P. angulata inhibited P. aeruginosa at zones ranging from 23±0.30 mm at 100 μg/ml to 13.00±0.20 mm at 50 μg/ml, whereas the aqueous crude extracts showed potency against P. aeruginosa at dose dependent concentrations ranging from 10±0.30 mm at 50 μg/ml to 13.00±0.30 mm at 250 μg/ml. Here, inhibition zone increased as concentration was increased. Ethanolic P. angulata crude extracts exhibited potency against S. aureus, recording a minimum zone of inhibition at 12.00±0.40 mm at 50 μg/ml and maximum zone of inhibition of 21.00±0.30 mm at 250 μg/ml. At lower concentration of 50 μg/ml, the combination of ethanolic E. hirta and P. angulata inhibited S. aureus at a zone of inhibition of 2 mm for the combination of the crude aqueous extracts; P. aeruginosa was inhibited at the zone of 1.0 mm with extract concentration of 50 μg/ml. A one-way analysis of variance (ANOVA) of the above values compared with the activity of Ciprofloxacin (positive control) indicated significant inhibitory activity by the unformulated P angulata and E hirta ethanolic crude extracts. Conclusion: The study indicates that crude extracts of E. hirta and P. angulate are possible sources of natural antibacterial agents against both skin and wound infections caused by S. aureus and P. aeruginosa. © 2016 The Authors.

Source: UG
Extreme Connectedness between Green Bonds, Government Bonds, Corporate Bonds and Other Asset Classes: Insights for Portfolio Investors

This paper aims to examine the connectedness between green and conventional assets. particularly during a period of economic downturn. Specifically, we examine quantile-based time-varying connectedness between the green bond market and other financial assets using quantile vector autoregression (QVAR) from 9, 2018 to 10, 2021. We use daily prices of S&P U.S. Treasury Bond Index, S&P US Aggregate Bond Index, S&P US Treasury Bond Current 10Y Index, S&P 500 Bond Index, S&P 500 Financials index, S&P 500 Energy Bond Index and S&P 500, giving a total of 784 observations, and using Composite Index as a representative of conventional assets classes and S&P Green Bond Index to denote the green bond market. The results show the connectedness between green bonds and the conventional asset classes intensified during the outbreak of the Coronavirus pandemic (COVID-19) as investors shifted their investment towards fixed income assets due to the plunge in the prices of stocks and commodities. The results also shows that green bonds are strongly connected with treasury bonds, aggregate bonds and bond index, as they share similarities with respect to issuance, risk and governance. Connectedness is weak in the case of composite index and energy bond index, as their prices do not have substantial influence on the green bond market. The study highlights the hedging and diversification benefits of green bonds. We have several implications for portfolio managers, policymakers, and researchers.

Source: UG
Extreme value modelling of Ghana stock exchange index

Modelling of extreme events has always been of interest in fields such as hydrology and meteorology. However, after the recent global financial crises, appropriate models for modelling of such rare events leading to these crises have become quite essential in the finance and risk management fields. This paper models the extreme values of the Ghana stock exchange all-shares index (2000–2010) by applying the extreme value theory (EVT) to fit a model to the tails of the daily stock returns data. A conditional approach of the EVT was preferred and hence an ARMA-GARCH model was fitted to the data to correct for the effects of autocorrelation and conditional heteroscedastic terms present in the returns series, before the EVT method was applied. The Peak Over Threshold approach of the EVT, which fits a Generalized Pareto Distribution (GPD) model to excesses above a certain selected threshold, was employed. Maximum likelihood estimates of the model parameters were obtained and the model’s goodness of fit was assessed graphically using Q–Q, P–P and density plots. The findings indicate that the GPD provides an adequate fit to the data of excesses. The size of the extreme daily Ghanaian stock market movements were then computed using the value at risk and expected shortfall risk measures at some high quantiles, based on the fitted GPD model.

Source: UG
Extremely high Li and low δ 7Li signatures in the lithospheric mantle

Geochemical behavior of lithium (Li) in mantle processes is generally explained by: (1) Li diffuses into minerals from melts, faster in clinopyroxene than in olivine, creating isotopically lighter-Li clinopyroxene and heavier-Li olivine; (2) Partitioning of Li changes with temperature, and as cooling proceeds Li diffuses into clinopyroxene from olivine, also resulting in low-δ 7Li clinopyroxene and high-δ 7Li olivine, similar to the result of process (1). Our results obtained from highly carbonatite-metasomatized peridotite xenoliths from the Western Qinling reveal that the minerals of these xenoliths contain extremely high Li in a range of 2-16ppm for olivine, 2-43ppm for orthopyroxene, and up to 75ppm for clinopyroxene. Secondly, olivines have much lower δ 7Li (down to -42‰) relative to co-existent pyroxenes. Above observations provide important insights into the behavior of Li during mantle processes. One explanation is that the fractionation of Li strongly depends on the metasomatic medium. Alkaline melts, particularly Na-rich carbonatitic melts, which have high Li contents (~200ppm) but mantle level δ 7Li (3-5‰), tend to effectively transfer 6Li into olivine and 7Li into pyroxene, while silicate melts behave on the contrary. Alternative might be the existence of a reservoir with a high Li content but low δ 7Li, like eclogite, in the mantle since the 7Li released into the overlying mantle wedge during dehydration. This study reveals the distinctive behavior of Li between the carbonatite and silicate metasomatism in the mantle. © 2011.

Source: UG
Extrusion cooking of rice-groundnut-cowpea mixtures - effects of extruder characteristics on nutritive value and physico-functional properties of extrudates using response surface methodology

Response surface methodology was used to study the effect of extruder characteristics on product quality of rice-groundnut-cowpea extrudates using a single-screw extruder. The combined effect of cowpea (0-20%), groundnut (0-10%) and feed moisture (12.02-44.06%) were used to formulate the products. Product moisture, protein, fat, ash, bulk density, expansion ratio, water absorption capacity (WAC) and swelling capacity were determined. Well-expanded rice-legume blend extrudates of less bulk density and lower moisture content were produced at low feed moisture. Addition of legumes resulted in significant increases in protein, fat and ash contents of the rice-legume extrudates while increasing cowpea increased all the physico-functional properties. The models developed gave R 2 values ranging from 64.01% (WAC at 70C) to 86.5% (bulk density) and suggested that the optimal process variables of low feed moisture (10-12%), cowpea level (20%) and groundnut level (10%) would produce ready-to-eat puffed snack with enhanced nutritive value and physico-functional properties from rice-groundnut-cowpea blend extrudates. © 2011 Wiley Periodicals, Inc.

Source: UG
Eye health knowledge and health-seeking behaviours in Ghana

Background: To improve access to comprehensive eye health services within the community, an intervention study that sought to integrate primary eye care (PEC) into existing primary health care (PHC) services, namely Community-based Health Planning and Services (CHPS), was conducted. Aim: To improve access to eye health at community level. Setting: The study was conducted in Northern, Eastern and Western Regions of Ghana. Methods: The study was a cross-sectional exploratory study, which employed both qualitative and quantitative methods. It used multistage cluster randomised sample design. The study involved a household survey, observation, focus group discussions (FGDs), in-depth interviews (IDIs) and informal discussions and case narratives. Results: The findings of the baseline survey covered information on the eye health knowledge, and health-seeking behaviours at community level. Out of the total 1760 people interviewed, 52.5% were women. The educational level of the respondents was low, 35.7% had no education and only 3% had tertiary education. All the study communities, including 67% of survey respondents, said eye disease was the third most common health problem. Overall knowledge about specific diseases was low. Only 3% and 5% of respondents mentioned trachoma and glaucoma, respectively, as a cause of blindness. All community members tended to either seek help from the practitioner closest to them or else alternate between different practitioners. Conclusion: The study showed that eye disease was a common health problem in all the communities. The community members desired eye care services manned by trained personnel close to them. Using CHPS appeared to be an option that can greatly improve access to eye care services in Ghana.

Source: UG
Fabrication and Density Functional Theory Calculations of Bromine Doped Carbon Nitride Nanosheets with Enhanced Photocatalytic Reduction of CO2 into Solar Fuels

A promising technology to address the global environmental challenges and solar-to-fuel conversion development is photocatalysis. Thus, this study was conducted to fabricate ultrathin Br doped g-C3N4 nanosheet for photocatalytic reduction of CO2 into solar fuels. The sample was produced by a mixture of dicyandiamide with ammonium bromide (NH4Br) in water, dried, calcinated, and exfoliated in methanol by ultrasonication. Compared to the pure g-C3N4 NS, the g-C3N4 NS-Br (0.5g) sample exhibited unique characteristics such as high porosity, large surface area, excellent visible light harvesting ability, effective charge separation, and mobility of charge carriers with enhanced photocatalytic CO2 reduction into solar fuels (i.e., CH4 and CH3OH). DFT calculation indicated that the sample possesses an excellent electronic band structure with band-gap energy to be 2.05 eV closed to 2.45 eV obtained from the experiment. The electronic band alignment structure favored a significantly higher CO2 photocatalytic reduction of 0.4 μmolh−1 g −1 of CH4 and 0.6 μmolh−1 g −1 of CH3OH formation, which is 4.0 and 7.5 times higher than the pure g-C3N4 NS. A combination of nanostructure tuning and doping produced a synergistic effect for enhancing photocatalytic activity and have potential applications in various fields.

Source: UG
Fabrication of novel kaolin-reinforced hydroxyapatite scaffolds with robust compressive strengths for bone regeneration

In this study, hydroxyapatite (HAp) microparticles obtained from animal bones were synthesized, and for the first time, HAp was reinforced with beneficiated kaolin using the sol-gel route to improve the mechano-biological properties of the bioceramic materials. The non-reinforced HAp as well as the reinforced samples (K-HAp) were sintered at 900, 1000 and 1100 ◦C to consolidate the mixture and detailed physico-chemical and mechanical characterizations was conducted. In-vitro experiments in phosphate buffer saline and simulated body fluid were used to confirm the degradability and compatibility of the HAp-derived bioceramic materials, respectively. XRD signatures showed that a dominant phase of hydroxyapatite was formed at all sintering temperatures (900, 1000, 1100 ◦C). The calcium to phosphate ratio (Ca/P) of the K-HAp-900 sample was approximately 1.67, which is the Ca/P ratio for stoichiometric hydroxyapatite prepared from synthetic sources. The active surface areas of the produced kaolin reinforced bioceramic materials: K-HAp 900–1100,were 0.9770, 0.2159 and 0.8659 m2/g, respectively, while the obtained micropore volumes were 0.000397, 0.001287, and 0.000334 cm3/g, respectively. At 900, 1000 and 1100 ◦C, compressive strengths (after applying the compaction pressure) with a value of 5.67, 6.33 and 7.66 MPa were obtained for the kaolin reinforced bioceramic materials, respectively. The mechanical measurement data further confirms that the reinforced bioceramic materials are suitable for human trabecular bone as the proposed scaffolds were endowed with an improved mechanical strength matching the bearable range of trabecular bone (2–12 MPa). In-vitro experiments showed the degradability and compatibility of the scaffolds. A relative neutral pH was maintained for sample K-HAp 900, and this sample also showed inhibitory potentials for bacterial strain (E. Coli).

Source: UG
Fabrication, Properties, and Performance of Polymer-Clay Nanocomposites for Organic Dye Removal from Aqueous Media

Methylene blue dye (MB dye) is a harmful contaminant for wastewater streams of industries and is harmful to human and aquatic life. An ecofriendly sugar templating process was used to generate porous bentonite/polydimethylsiloxane (PB) and porous magnetite nanoparticles/bentonite/polydimethylsiloxane (PBNP) composite absorbents to remove MB dye in this study. During the infiltration of PDMS solution into the sugar template in the vacuum chamber, bentonite and magnetite particles were integrated on the surface of the PDMS, and the porous structure was generated during the leaching out of sugar particles in water. The absorbents were characterized using Fourier infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The absence of the methyl bond at 2924 cm-1 and phenol bond at 3325 cm-1 in the FTIR spectra of the formed membrane proves that the food grade sugar was completely removed. The SEM images confirm that porosity was achieved as well as uniform mixing of the in the formation of composite. MB dye was effectively removed from wastewater using the as-prepared composite as absorbent. The removal efficiencies of the composite PBNP and PB were ~91% and ~85%, respectively. The experimental data was applied to pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models as well as the Dubinin-Radushkevich, Harkins-Jura, and Elovich models for the adsorption isotherm. The data was found to fit the pseudosecond-order and Elovich models, respectively. The results show that the presence of magnetite nanoparticles improved MB dye removal significantly.

Source: UG
Face detection based on multilayer feed‐forward neural network and Haar features

Fast and accurate detection of a facial data is crucial for both face and facial expression recognition systems. These systems include internet protocol video surveillance systems, crime scene photographs systems, and criminals' databases. The aim for this study is both improvement of accuracy and speed. The salient facial features are extracted through Haar techniques. The sizes of the images are reduced by Bessel down-sampling algorithm. This method pre- served the details and perceptual quality of the original image. Then, image normalization was done by anisotropic smoothing. Multilayer feed-forward neural network with a back-propagation algorithm was used as classifier. A detection accuracy of 98.5% with acceptable false positives was registered with test sets from FDDB, CMU-MIT, and Champions databases. The speed of exe- cution was also promising. An evaluation of the proposed method with other popular detectors on the FDDB set shows great improvement.

Source: UG
FaceNet recognition algorithm subject to multiple constraints: Assessment of the performance

Literature has it that the performance of most face recognition algorithms still decline in multiple constrained environments (Occlusions and Expressions), despite the achieved successes of deep learning face recognition algorithms. Using expression variant test face images syn thetically occluded at 30% and 40% rates, the study evaluated the performance of FaceNet deep learning model for face recognition under the aforementioned constraints and when three (3) statistical multiple imputation methods (Multivariable Imputation using Chain Equations (MICE), MissForest and Regularized Expectation Maximization (RegEM)) are adopted for occlu sion recovery. Results of the study showed improved recognition rates of the study algorithm when the imputation-based recovered faces were used for recognition compared with using their multiple constrained counterparts. However, test faces reconstructed with the MissForest imputation method were more accurately recognized using the FaceNet deep learning algorithm. Furthermore, the study demonstrated that some simple augmentation schemes sufficed to further enhance the performance of the FaceNet model. Specifically, the FaceNet algorithms gave the highest average recognition rates (85.19% and 79.5% for 30% and 40% occlusion levels respectively) under augmentation scheme IV (slight rotations, horizontal flipping, shearing, brightness adjustments, and stretching) using MissForest as the de-occlusion mechanism. The study also found that, no disparity existed in its performance with the choice of either Support Vector Machines (SVM) or City Block (CB) for classification under augmentation scheme IV. The study recommends using the MissForest imputation method in dealing with moderately high occluded test faces with varying expressions to enhance the performance of the FaceNet face recognition model.

Source: UG
Facets of Cross Border Commuting in the Central European Region and the (Re)production of inequalities

ABSTRACT This presentation examines intra-European labour mobility from the perspective of social inequality and social stratification. The focus lies on cross-border commuters from the border regions of the Czech Republic, Slovakia and Hungary who work in Austria. The aim is to shed light on causes and forms of changes in inequality as a consequence of transnational labour involvement in the Central European Region (CENTROPE). This region is of particular interest, as it has a long history of cross-border mobility and social exchange, from the Habsburg Monarchy to the postwar period and after 1989, culminating in the accession to the EU in 2004. Since May 1st, 2011, all citizens were given the freedom to seek employment according to their skills in Austria. The superordinate research question of the study is: How do transnational labour practices in the Central European Region relate to the (re)production of social inequalities? In order to answer this question, the paper looks at influencing factors systematically linking both labour markets and mobility: the legal framework, the macro-economic context, the welfare state regime, the economic structure of the local region, employers’ practices and commuters’ life worlds.

Source: UG
Facilitating active social presence and meaningful interactions in online learning

Online learning has minimized many barriers and constraints that are common in traditional learning environments. However, due to the absence of face-to-face contacts, students and instructors are usually faced with the lack of active social presence and meaningful interactions in online learning. This article explores a review of the literature on social presence and various types of interactions in online learning environments in the context of a class project. The findings suggest need for online instructors to explore effective ways to design and facilitate active social presence and meaningful interactions in online learning.

Source: UG
Facilitating change processes in group-based behaviour change interventions in rural African contexts: practical lessons from Ghana

Evidence from implementation research suggests that group-based behaviour change interventions (GBCIs) can encourage the development of peer support, promote psychosocial skills, and facilitate collaborative therapeutic relationships. However, although the mechanisms of action that mediate the behaviour change process have been extensively described in other settings, less is known about the implementation strategies and contextual factors that actuate the reported behaviour changes among programme participants in Ghana and sub-Saharan Africa, more generally. We draw on insights from the literature and field experiences from designing, implementing, and evaluating GBCIs across several rural and peri-urban communities in Ghana to discuss a range of theoretical, methodological, and contextual factors that facilitate the behaviour change process in programme participants. We offer suggestions to guide researchers to envision and manage potential challenges with the programme development and implementation processes. We propose that intervention programmes designed to facilitate health behaviour change in the defined context should (i) have a context-relevant focus, (ii) be coherent and well-structured, (iii) have explicit techniques to facilitate inter-personal and intra-personal change processes, (iv) include appropriate mechanisms to monitor and assess the progress of the interventional sessions; and (v) be implemented by trained facilitators with a deep knowledge of the sociocultural values and norms of the target group and of the principles and theories underlying the intervention programme. We envisage that these insights could serve to guide the design, implementation, and evaluation of contextually-tailored and potentially effective GBCIs that align with the needs, capacities, and circumstances of the local population.

Source: UG