156 research outputs found
Drug-Resistant tuberculosis in Ethiopia: Characteristics of cases in a referral hospital and the implications
No full textBackground: Tuberculosis (TB) programs should design intervention strategies based on the sound knowledge of the existing local epidemiology and sociodemographic characteristics of drug-resistant-TB (DR-TB) cases. The aim of the study was to characterize the pulmonary multidrug-resistant (MDR) and rifampicin-resistant (RR) TB cases enrolled in a referral hospital at Addis Ababa, Ethiopia, called All Africa Leprosy, Tuberculosis, Rehabilitation and Training (ALERT) Hospital. Methods: We conducted a descriptive study based on retrospective review of medical records of 340 pulmonary MDR/RR-TB cases enrolled in ALERT Hospital from November 2011 to December 2016. To characterize the cases, we described the distribution of demographic and clinical characteristics. To compare the distribution of demographic and clinical characteristics between male and female cases, we used Pearson's Chi-squared test. Results: Males accounted for 52.9% of the 340 cases. Nine out of ten cases were in the age group of 15–44 years. Sputum acid-fast bacilli smear-positive and human immunodeficiency virus-coinfected cases constituted 63.7% and 18.1% of cases, respectively. The proportion of new cases increased through the years from nil in 2011 to 21.4% in 2016. Adult males above 24 years constituted more than three quarters (77.2%) of the total male cases, while adult females in this age group constituted 56.9%. The age distribution between male and female cases showed significant differences (P < 0.001). Conclusion: There is age disparity between male and female cases with high impact of MDR/RR-TB on productive adult male population. The transmission potential for DR-TB is also high in the community
Numerical simulation of Spontaneous Imbibition of Smart Water into Preferentially oil-wet Carbonate using ECLIPSE 100
No full textMaster's thesis in Petroleum technologySpontaneous imbibition (SI) is the main recovery mechanism in low matrix perme-
ability, naturally fractured reservoirs. However, for imbibition to occur, the reservoir
rock should be preferentially water-wet. Several studies have indicated that smart
water may increase the water-wetness of an oil-wet carbonate reservoirs. Published
experimental data suggest that sulfate ion in the injected
fluid can alter wetting
state of the carbonate from preferentially oil-wet to water-wet.
Numerical and analytical models have been developed to describe SI process in
carbonate reservoirs. The suggested models attempt to capture the complex inter-
actions among different phases and species during SI process. In this study, using
the already existing surfactant model of ECLIPSE 100 simulator, dynamic e ect of
adsorption of sulfate on wettability alteration in core scale is modelled. Wettability
change option of the surfactant model is employed to capture change in wettability
due to adsorption of sulfate ion. Using the procedure of weight factor, wettability of
the core shifts dynamically from oil-wet to water-wet conditions proportional to the
adsorbed amount of sulfate. Laboratory experiments have been matched with the
established procedure.
The result showed that the wettability change option under surfactant model in
ECLIPSE 100 is capable of modelling the change in wettability due to adsorption of
sulfate ion. The model is able to predict experimental data using the procedure of
weight factor. Moreover, a correlation between weight factor and Amott wettability
index is established. The basic model that could be used for further investigations
or upscaling to field scale is established
The Future in Mind: Aspirations and Forward-Looking Behaviour in Rural Ethiopia
No full textresearch funding by the UK Department for International Development (DFID) as part of the iiG, a research programme to study how to improve institutions for pro-poor growth in Africa and South-Asia. The views expressed are not necessarily those of DFID. Bernard and Taffesse were funded by Seven in the Open Enterprise Solutions to Poverty competition to produce the documentaries used in the intervention. They acknowledge the support of the IFPRI Development Strategy and Governance and Markets, Trade and Institutions divisions. The authors thank Fanaye Tadesse and Ibrahim Worku for excellent research assistance and Bezabih Tesfaye, Tewodros Abate and the IFPRI team for their fieldwork management. The views expressed in this document are not necessarily those of the funders. The authors thank Karla Hoff, Johannes Haushofer
Ethiopia water resources
No full textAny opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration.The Bale Mountains of south-central Ethiopia comprise one of Africa's least-studied massifs, and are home to the world-renowned Bale Mountain National Park. A designated Biodiversity Hotspot, the area also serves as the headwaters for five major rivers that flow out of the mountains, supporting 12 million people in the arid lowlands to the east. In recent years, development in the surrounding area has forced many agro-pastoralists into the highlands, and approximately 40,000 people now live within the park boundaries. Mapping the location and extent of the region's water resources has been identified as a key research need for local park officials and conservation groups as they work to sustainably accommodate this massive influx of people and livestock. Of particular concern are the region's numerous alpine lakes and wetlands, as they are essential for wildlife habitat, water quality, and discharge timing for both upstream and downstream users throughout the dry season. This study used environmental indices derived from Landsat 8 Operational Land Imager/Thermal Infrared data, topographic variables, and species distribution models to map all perennial alpine lakes and wetlands in the Bale Mountains. Resulting models of wetlands and lakes had classification accuracies of 97% and 100%, respectively. These represent the first comprehensive maps of their kind in Bale, and will facilitate the targeting of conservation and research efforts in the region. Additionally, the methodology is applicable in other remote areas around the world where field data is sparse and regular monitoring is needed.NASA DEVELOP.This material is based upon work supported by NASA through contract NNL11AA00B and cooperative agreement NNX14AB60A
Improving the electrocatlytic activity of cobalt oxide for acidic oxygen evolution reaction with bismuth dopants
No full textThe continued overuse of fossil fuels for energy purposes does not only exacerbate the environment pollution but also causes the depletion of these energy resources. This makes the development of sustainable energy sources, such as green hydrogen, urgent and essential. Currently hydrogen is produced through traditional fossil fuel reforming or dehydrogenation processes. These processes, however, produce greenhouse gases and deplete fossil fuels. In contrast to these processes, water splitting utilizes an abundant raw material (i.e., water) and generates less pollution, if any. As such, this method exhibits a significant potential for massive production of hydrogen and aligns well with the principles of green chemistry. The method is especially quite appealing to produce green hydrogen when coupled with sustainable energy sources such as solar and wind energy. However, the oxygen evolution reaction (OER), a key reaction required for water splitting, hinders the overall efficiency of water splitting due to its slow reaction kinetics and high overpotential resulting from its intricate four-electron transfer processes. Furthermore, in acidic electrolyte, where the abundance of protons results in an efficient hydrogen evolution reaction (HER), most catalysts are unfortunately inactive and highly unstable towards OER. Thus, constructing stable, highly active acidic OER catalysts is of vital importance.
With this aim in mind, and to solve the issues mentioned above, a kind of high-performance acidic OER catalyst that is composed of bismuth-cobalt oxide annealed on fluorine-doped tin oxide (FTO) glass substrate is designed and synthesized. In the design of the catalyst, fundamental principles are considered. Co is included as it conforms with the so-called Sabatier principle well, which entails not only high catalytic activity, but also good stability in catalysts. Meanwhile, Bi is chosen as it is expected to work as a catalytically active center when it is with Co for OER. It is also expected to improve the density of active sites and oxygen vacancy in the catalysts, which are favorable for OER.
Additionally, catalysts containing Co and Bi in different ratios are synthesized to investigate the effects of their compositions on their electrocatalytic properties. The results show that Co9BiOx, which has a Co:Bi ratio of 9:1, exhibits the best electrocatalytic activity with the lowest overpotential (540 mV) at a current density of 10 mA·cm-2 and the lowest Tafel slope (113 mV·dec-1) to drive the OER. Its electrocatalytic activity is also found to be higher than those of the pristine Co3O4 and the catalysts prepared with other Co:Bi ratios. The high activity of the Co9BiOx, catalyst is accounted by its high electrochemical active surface area and double-layer capacitance. The participation of Bi in the electrocatalytic activities of the catalysts is further confirmed by density-functional theory (DFT) calculations.
This project’s findings not only highlight the potential of bismuth doping cobalt oxide to improve the acidic OER activity of this transition metal oxide, but also show the necessity of deeper investigations of p-block elements like bismuth for electrocatalytic applications. Furthermore, the research work leads to an eco-friendly catalyst for sustainable energy solutions.M.S.Includes bibliographical reference
Near-IR absorbing solar cell sensitized with bacterial photosynthetic membranes
No full textCurrent interest in natural photosynthesis as a blueprint for solar energy conversion has led to the development of a biohybrid photovoltaic cell in which bacterial photosynthetic membrane vesicles (chromatophores) have been adsorbed to a gold electrode surface in conjunction with biological electrolytes (quinone [Q] and cytochrome c; Magis et al. [2010] Biochim. Biophys. Acta 1798, 637–645). Since light-driven current generation was dependent on an open circuit potential, we have tested whether this external potential could be replaced in an appropriately designed dye-sensitized solar cell (DSSC). Herein, we show that a DSSC system in which the organic light-harvesting dye is replaced by robust chromatophores from Rhodospirillum rubrum, together with Q and cytochrome c as electrolytes, provides band energies between consecutive interfaces that facilitate a unidirectional flow of electrons. Solar I–V testing revealed a relatively high Isc (shortcircuit current) of 25 lA cm)2 and the cell was capable of generating a current utilizing abundant near-IR photons (maximum at ca 880 nm) with greater than eight-fold higher energy conversion efficiency than white light. These studies represent a powerful demonstration of the photoexcitation properties of a biological system in a closed solid-state device and its successful implementation in a functioning solar cell.Peer reviewedThis is the accepted version of the following article: Woronowicz, K., Ahmed, S., Biradar, A. A., Biradar, A. V., Birnie, D. P., Asefa, T. and Niederman, R. A. (2012), Near-IR Absorbing Solar Cell Sensitized With Bacterial Photosynthetic Membranes. Photochemistry and Photobiology, 88: 1467–1472. doi: 10.1111/j.1751-1097.2012.01190.x, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.2012.01190.x/abstrac
Knowledge, risk perception, and condom utilization pattern among female sex workers in Dire Dawa, Eastern Ethiopia 2016: a cross-sectional study
No full textIntroduction: in 2015, in Dire Dawa administration city, adult HIV prevalence was 3.26 with 9,523 HIV positive population, & 251 annual AIDS deaths. Female sex workers are one of the high-risk groups for contracting HIV. Therefore, this study has assessed the level of HIV/AIDS knowledge, risk perception and condom utilization pattern among female sex workers' in Diredawa city.
Methods: a cross-sectional study was conducted from April 15-June 25, 2016, in Dire Dawa among 156 female sex workers using convenient sampling method. Respondents were interviewed face-to-face using a pretested questionnaire. Training was provided to the data collectors and supervisors. Close supervision was done and double data entry was performed. Then the data were checked for completeness, consistency and entered into Epi Info v3.1 and analyzed using SPSS v20. The descriptive statistical analysis was used to compute frequency, mean, mode and proportion of the findings of this study. The results were presented using tables, charts, graphs, and texts.
Results: among the 156 female sex workers (FSWs), 99 (63.5%) had been working on commercial sex for more than one year, 92 (59%) were usually street-based, and 80 (51.3%) had partners between 2-3 per night. Only, 17 (10.9%) respondents mentioned three and above ways of HIV/AIDS transmission and prevention methods. Less than two-thirds (64.1%) of FSWs used a condom with all partners. One hundred thirty-eight (88.5%) of participants were engaged in unsafe sexual practice at least once since their engagement in sex work. Majority of FSWs (85.3%)) believed that their occupation is hazardous and 145 (92.9%) reported that they were unhappy being a commercial sex worker. Regarding risk perception, 79 (50.64%) and 37 (23.7%) of respondents perceived their chances of contracting HIV/STIs to be high and moderate respectively.
Conclusion: Knowledge about HIV/STIs and magnitude of condom utilization were good. However, a high number of unsafe sex and unsatisfactory risk perception attitudes were observed. Thus, a collaborative effort is needed to create awareness regarding risk perception attitude and increase the level of their practice towards the prevention of unsafe sex
Drug-Resistant tuberculosis in Ethiopia: Characteristics of cases in a referral hospital and the implications
No full textEarly Implanon Discontinuation and Associated Factors among Implanon User Women in Debre Tabor Town, Public Health Facilities, Northwest Ethiopia, 2016
No full textBackground. Implanon discontinuation closely related to higher rates of overall fertility rate, unwanted pregnancies, and induced abortion. This might have social and economic consequences. In Ethiopia the magnitude of early Implanon discontinuation and contributing factors is not well studied. Objective. To assess early Implanon discontinuation and associated factors among Implanon user women in Debre Tabor town, 2016. Methods. A facility based cross-sectional study was conducted from May 1 to August 2016 through face-to-face interview. A total of 449 Implanon user women were selected by systematic random sampling technique. Epi Info version 7 and SPSS version 20 were used for data entry and analysis, respectively. Factors associated with early Implanon discontinuation were analyzed using binary and multivariable logistic regression model. Variables with p value of <0.05 and 95% confidence interval were considered as statistically significant. Results. The overall proportion of early Implanon discontinuation among mothers was 65 % (95%, CI: 60.4%–69.5%). Having no children (AOR = 2.0, 95% CI = [1.3–4.5]), being not counseled for possible side effects (AOR = 1.50, 95% CI = [1.1–3.4]), having no appointment for follow-up (AOR = 2.6, 95% CI = [1.2–4.3]), and having developing side effects (AOR = 1.7, 95% CI = [1.5–4.4]) were found to be statistically significant factors associated with early Implanon discontinuation. Conclusion and Recommendation. Early Implanon discontinuation among mothers was found to be high. Hence, counseling about Implanon side effects and appointment for follow-up of Implanon users should be made to increase Implanon retention.</jats:p
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