80 research outputs found
Predicting Job Stress and Job Satisfaction among Registry Staff of Takoradi Technical University in Ghana: A Discriminant Analysis Approach
The purpose of this paper was to find out the variance of job satisfaction on four job stressors: management role, role ambiguity, role conflict and workload among registry staff of Takoradi Technical University (TTU) in Ghana. A survey research method was adopted for the study and a questionnaire was used to collect data from 85 registry staff in the University through a convenience sampling technique. A discriminant analysis was used to predict job satisfaction of the registry staff into whether I am satisfied with my job or I don’t like my job based on the four job related stressors. The classification model showed that 96.5% of the sampled registry staff were correctly classified as those who did not like their job or those who were satisfied with their job. The summary of canonical discriminant functions with canonical correlation value of 0.942 suggested the model explained 88.7 % of the variance for the job satisfaction in terms of four job related stressors: management role, work load, role conflict and role ambiguity. Furthermore, role conflict and role ambiguity topped the factors that the registry staff considered as precursors of job dissatisfaction. This research paper used discriminant analysis approach to group job satisfaction levels of registry staff based on four job stressors: management role, role conflict, role ambiguity and workload which would assist the management to minimise job stress in the University. Keywords: Job satisfaction, Job stress, Registry staff, Discriminant Analysis, Takoradi Technical University. DOI: 10.7176/JEP/11-30-15 Publication date:October 31st 202
Synthesis and Characterization of CdSe Nanocrystalline Thin Film by Chemical Bath Deposition Technique
A well adherent nanocrystalline thin film of cadmium selenide (CdSe) has been successfully deposited from chemical bath containing cadmium acetate, tartaric acid, ammonia and sodium selenosulphate, at a bath temperature of 85 0C and a pH of 9.5. The films were characterized using a variety of techniques. Powder X-ray diffraction revealed a cubic phase of CdSe nanocrystalline thin film with preferred orientation along the (111) plane. The SEM micrographs showed the film surface was composed of spherically shaped grains over the entire glass substrate. The elemental composition of the thin film was confirmed by energy dispersive X-ray spectroscopy. The optical band gap energy was found to be 1.86 eV
West African Summer Monsoon Precipitation Variability as Represented by Reanalysis Datasets
Focusing on West Africa, a region riddled with in situ data scarcity, we evaluate the summer monsoon monthly rainfall characteristics of five global reanalysis datasets: ERA5, ERA-Interim, JRA-55, MERRA2, and NCEP-R2. Their performance in reproducing the West African monsoon (WAM) climatology, interannual variability, and long-term trends for the main monsoon months are compared to gauge-only and satellite products. We further examine their ability to reproduce teleconnections between sea surface temperatures and monsoon rainfall. All reanalyses are able to represent the average rainfall patterns and seasonal cycle; however, regional biases can be marked. ERA5, ERA-Interim, and NCEP-R2 underestimate rainfall over areas of peak rainfall, with ERA5 showing the strongest underestimation, particularly over the Guinea Highlands. The meridional northward extent of the monsoon rainband is well captured by JRA-55 and MERRA2 but is too narrow in ERA-Interim, for which rainfall stays close to the Guinea Coast. Differences in rainband displacement become particularly evident when comparing strong El Niño Southern Oscillation (ENSO) years, where all reanalyses except ERA-Interim reproduce wetter Sahelian conditions for La Niña, while overestimating dry conditions at the coast except for NCEP-R2. Precipitation trends are not coherent across reanalyses and magnitudes are generally overestimated compared to observations, with only JRA-55 and NCEP-R2 displaying the expected positive trend in the Sahel. ERA5 generally outperforms ERA-Interim, highlighting clear improvements over its predecessor. Ultimately, we find the strengths of reanalyses to strongly vary across the region
Seasonality and trends of drivers of mesoscale convective systems in southern West Africa
Mesoscale convective systems (MCSs) are the major source of extreme rainfall over land in the tropics and are expected to intensify with global warming. In the Sahel, changes in surface temperature gradients and associated changes in wind shear have been found to be important for MCS intensification in recent decades. Here we extend that analysis to southern West Africa (SWA) by combining 34 years of cloud-top temperatures with rainfall and reanalysis data. We identify clear trends in intense MCSs since 1983 and their associated atmospheric drivers. We also find a marked annual cycle in the drivers, linked to changes in the convective regime during the progression of the West African monsoon. Before the peak of the first rainy season, we identify a shear regime where increased temperature gradients play a crucial role for MCS intensity trends. From June onward, SWA moves into a less unstable, moist regime during which MCS trends are mainly linked to frequency increase and may be more influenced by total column water vapor. However, during both seasons we find that MCSs with the most intense convection occur in an environment with stronger wind shear, increased low-level humidity, and drier midlevels. Comparing the sensitivity of MCS intensity and peak rainfall to low-level moisture and wind shear conditions preceding events, we find a dominant role for wind shear. We conclude that MCS trends are directly linked to a strengthening of two distinct convective regimes that cause the seasonal change of SWA MCS characteristics. However, the convective environment that ultimately produces the most intense MCSs remains the same
Farmer’s observation on climate change impacts on maize (Zea mays) production in a selected agro-ecological zone in Ghana
Although maize farmers may not have a clear understanding of climate change, they live close to natural resources and are among the first in perceiving and reacting to environmental changes. They have observed and felt the effects of decreasing rainfall, emphasizing changes in the regularity, length, intensity and timing of rainfall; increasing air temperature, increasing sunshine intensity and seasonal changes in rainfall pattern which is affecting their farming practices. Moreover, farmers are also aware of the interacting effect between bad management practices and changes in climate. For instance, deforestation and clearing of riparian vegetation is considered a major factor increasing soil erosion; the use of agricultural chemicals close to the rivers and streams create hazards for the environment. The study indicates that changes in the onset and cessation of rain have negative impact on maize production and this pose a serious threat to household food security since maize is the staple food of most Ghanaians. Consequently, effective and efficient adaptation and mitigation measures should be promoted to prepare stakeholders in maize production systems to enhance their resilience and flexibility
Theoretical Modeling of the Impact of Salt Precipitation on CO2 Storage Potential in Fractured Saline Reservoirs
Deep saline reservoirs have the capacity to hold large volumes of CO2. However, apart from the high brine salinity, which poses an injectivity challenge, a high percentage of saline reservoirs are also fractured. The mechanisms of drying and salt precipitation and the resulting impact on CO2 injection are unique in fractured reservoirs. Analytical models were developed to investigate the impact of salt precipitation on CO2 injectivity and storage capacity. Two types of fractured saline reservoirs were considered: type I fractured reservoirs, where storage capacity and injectivity are contributed by only fractures, and type II fractured reservoirs, where both fractures and the adjacent rock matrix blocks contribute to CO2 storage and injectivity. We found that, depending on the initial brine salinity, salt precipitation could severely impair CO2 injectivity and reduce storage capacity. Salt precipitation had a fourfold impact on CO2 injectivity compared to storage capacity. Type I reservoirs with high irreducible brine saturation were less susceptible to salt clogging in the fractures. The results also suggest that fractures with rectangular aperture were less likely to be plugged by salt compared to elliptical fractures. Contrary to previous reports, some fractured deep saline reservoirs may not be suitable for CO2 storage. Generally, type II fractured reservoirs were found to be more suitable for CO2 storage in terms of susceptibility to salt clogging. The findings provide valuable understanding of the mechanisms and effect of drying and salt precipitation on CO2 storage potential, making a strong case for CO2 storage in naturally fractured deep saline reservoirs.publishedVersio
Characteristics of severe anemia and its association with malaria in young children of the Kassena-Nankana District of northern Ghana.
Severe anemia is thought to be the principal underlying cause of malaria death in areas of intense seasonal malaria transmission such as the Kassena-Nankana District of northern Ghana. Factors associated with severe anemia in young children, 6-24 months old, were elucidated by analyzing results of 2 malaria-associated anemia surveys (1996, 2000), separated by 4 years, but conducted in the same community and at the same seasonal time point. Age-adjusted comparison confirmed that the proportion of severely anemic children and overall mean hemoglobin (Hb) levels in the November 2000 sample were significantly improved over those of the 1996 sample (17.5 versus 26.4%, P = 0.03; Hb 7.5 versus 6.9 g/dL, P = 0.002). Weight-for-age Z-scores also indicated a significant improvement in the 2000 sample (-1.93 versus -2.20, P or = 6.0 g/dL, those with severe anemia (Hb < 6.0 g/dL) were older, more frequently parasitemic (odds ratio [OR], 1.60; 95% confidence interval [CI], 1.08-2.35), more often febrile (OR, 2.44; 95% CI, 1.71-3.48), and predominantly male (OR, 1.50; 95% CI, 1.05-2.13). An association was identified in both surveys between severe anemia and residence in the northern part of the district, but no clear link was observed in relation to irrigation. Blood transfusions, a likely surrogate index of severe anemia in young children, followed a distinct seasonal pattern. Evidence suggests that dramatic peaks and troughs of severe anemia are regular and possibly predictable events that may be used to gauge the health and survival of young children in this area
A Randomized, Double-Blind, Placebo-Controlled, Dose-Ranging Trial of Tafenoquine for Weekly Prophylaxis against \u3ci\u3ePlasmodium falciparum\u3c/i\u3e
Tafenoquine is a promising new 8-aminoquinoline drug that may be useful for malaria prophylaxis in nonpregnant persons with normal glucose-6-phosphate dehydrogenase (G6PD) function. A randomized, doubleblind, placebo-controlled chemoprophylaxis trial was conducted with adult residents of northern Ghana to determine the minimum effective weekly dose of tafenoquine for the prevention of infection by Plasmodium falciparum. The primary end point was a positive malaria blood smear result during the 13 weeks of study drug coverage. Relative to the placebo, all 4 tafenoquine dosages demonstrated significant protection against P. falciparum infection: for 25 mg/week, protective efficacy was 32% (95% confidence interval [CI], 20%–43%); for 50 mg/week, 84% (95% CI, 75%–91%); for 100 mg/week, 87% (95% CI, 78%–93%); and for 200 mg/week, 86% (95% CI, 76%–92%). The mefloquine dosage of 250 mg/week also demonstrated significant protection against P. falciparum infection (protective efficacy, 86%; 95% CI, 72%–93%). There was little difference between study groups in the adverse events reported, and there was no evidence of a relationship between tafenoquine dosage and reports of physical complaints or the occurrence of abnormal laboratory parameters. Tafenoquine dosages of 50, 100, and 200 mg/week were safe, well tolerated, and effective against P. falciparum infection in this study population
Classification of large-scale environments that drive the formation of mesoscale convective systems over southern West Africa
Mesoscale convective systems (MCSs) are frequently observed over southern West Africa (SWA) throughout most of the year. These MCS events are the dominant rain-bearing systems, contributing over 50 % of annual rainfall over SWA. However, it has not yet been identified what variations in typical large-scale environments of the seasonal cycle of the West African monsoon may favour MCS occurrence in this region. Here, nine distinct synoptic states are identified and are further associated with being a synoptic-circulation type of either a dry, transition, or monsoon season using self-organizing maps (SOMs) with inputs from reanalysis data. We identified a pronounced annual cycle of MCS numbers with frequency peaks in April and October that can be associated with the start of rainfall during the major rainy season and the maximum rainfall for the minor rainy season across SWA, respectively. Comparing daily MCS frequencies, MCSs are most likely to develop during transition conditions featuring a northward-displaced moisture anomaly (2.8 MCSs per day), which can be linked to strengthened low-level westerlies. Considering that these transition conditions occur predominantly during the pre- and post-monsoon period, these patterns may in some cases be representative of monsoon onset conditions or a delayed monsoon retreat. On the other hand, under monsoon conditions, we observe weakened low-level south-westerlies during MCS days, which reduce moisture content over the Sahel but introduce more moisture over the coast. Finally, we find a majority of MCS-day synoptic states exhibiting positive zonal wind shear anomalies. Seasons with the strongest zonal wind shear anomalies are associated with the strongest low-level temperature anomalies to the north of SWA, highlighting that a warmer Sahel can promote MCS-favourable conditions in SWA. Overall, the SOM-identified synoptic states converge towards high-moisture and high-shear conditions on MCS days in SWA, where the frequency at which these conditions occur depends on the synoptic state
Sub-Saharan Africa's Mothers, Newborns, and Children: How Many Lives Could Be Saved with Targeted Health Interventions?
As part of the series on maternal, neonatal, and child health in sub-Saharan Africa, Robert Black and colleagues estimated mortality reduction for 42 countries and conclude that the use of local data is needed to prioritize the most effective mix of interventions
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