524 research outputs found
Screening Potential Probiotic Bacteria as Starter Culture from Traditional Fermented Ensete (Ensete Ventricosum (WELW) Cheesman
Fermented Ensete (Ensete ventricosum (Welw) Cheesman) commonly called false banana is an important nutrient source in southern part of Ethiopia. This study aimed at screening potential probiotic bacteria from a traditional fermented Ensete. A total of 12(twelve) samples were collected from local traditional fermented Ensete. Various morphological and biochemical tests were performed for screening of the potential probiotic bacteria as starter culture. Media optimization was carried out for cultivation of the potential isolate. The potential isolate was found to be gram positive, non motile, negative for (Catalase, indole). This bacterium had broad range of pH 4.0 – 8.0 and temperature of 25-40 (0c). It was tolerant to 1-4% salt concentration. High growth rate of the isolate was observed in the presence of 2 % glucose and 0.2 % peptone. The optimum temperature and pH for high biomass production was observed at 370c and pH of 7. Fermentation of Ensete with isolate increased the nutritional value and aroma of a food as well. The isolate was found to be Lactobacilli sp. CH2 which fulfills the required criteria for a probiotic such as tolerance to such as high salt, low pH, body temperature range. The result in this study is reproducible and reliable for further processing of Ensete in the local community. Molecular study should be done for characterization of this potential strain. Keywords: Lactobacilli, Prebiotic, Probiotic, Starter culture
Implications of groundwater quality to corrosion problem and urban planning in Mekelle area, Northern Ethiopia
Surface and groundwater chemistry being an important factor in urban planning and infrastructure development, present paper tries to present the problems of corrosiveness due to groundwater chemistry in Mekelle city. Iron corrosion in distribution systems and engineering structures are common problems in many urban areas. Corrosiveness of groundwater at different localities in Mekelle and its environs has been evaluated on the basis of AAS-UV spectrophotometer-generated hydro-geochemical data. Corrosiveness of water was estimated by using corrosion indices like Larson Index, LI and Aggressive Index, AI and total dissolved solids, total carbonate hardness, chloride and sulphate data were evaluated to estimate aggressiveness of the water samples on iron pipes. Analyses of the results have shown that most of the samples from boreholes and hand dug wells compared to spring samples, are potentially aggressive. The result shows that 66.7% spring, 81.3% shallow hand dug wells and 81% borehole water samples have a Larson index (LI) above 0.5, a threshold of corrosiveness of water. This study highlights the basic characteristics of surface and groundwater chemistry and its potential hazard for corrosion of pipes, and provides a baseline information and awareness to the city planners for urban management
Experimental study of physical, chemical and mechanical properties of enset and sisal fibers
The properties of composites depend on type and properties of the fiber, fiber structure and treatment. In this study, effects of NaOH treatment on the physical, chemical and mechanical properties of fibers collected from South-West Ethiopia were investigated using untreated, 5% and 10% alkali treated enset and sisal fibers. The effects of NaOH on diameter, moisture absorption, density, lignin and hemicellulose was experimentally studied. In addition, tenacity of both fibers was investigated by using optical microscopy, Fourier transform infrared spectroscopy and single fibers tensile strength tester. The 5% and 10% NaOH treatment significantly improved the moisture absorption and diameters. The moisture absorption of 5% and 10% NaOH treated enset fibers improved by 33% and 34%, while the same treatment on sisal fibers improved the moisture absorption by 30% and 40% respectively. The 5% NaOH treated enset and sisal fiber showed better tenacity, which is an indication of the tensile strength of single fiber, than untreated and 10% NaOH treated fibers. Improving moisture content, diameter, lignin and hemicellulose contents of the fibers contributes to better bonding as interlock with the matrix materials enhancing the mechanical properties of composites.publishedVersio
Study of Machinability in Drilling Operation of Enset–Sisal Hybrid Polyester Composite
Due to their light weight, low density, high-specificity strength, and ease of fiber surface treatment, natural-fiber-reinforced composites are recognized as the most suitable materials for interior part applications. Moreover, natural fibers are widely accessible and environmentally friendly. The fabricated parts are assembled predominantly by fastening using drilled holes, which makes drilling operations common machining processes for the composite parts. Damage occurs at the entry and exit surfaces of drilled holes. In this study, hand layup procedures are used to create unidirectional and woven forms of 1:1 ratio enset (false banana)/sisal hybrid polyester composites that have been treated with 5% NaOH. The drill operation was performed using a computer numerical control (CNC) drill machine with high-speed steel twist drill. A Taguchi design tool was used to complete the analysis. The experiments were conducted at different levels of drilling speeds: 600, 1200, and 1800 rpm. Feed rates of 0.1, 0.2, and 0.3 mm/rev and drill bit diameters of 6, 9, and 12 mm were used. These were determined to be the study parameters that influenced the delamination factors (Fd) and surface roughness (SR) of the hybrid composite drilled parts. Delamination occurred at the entry and exit surfaces of the drilled holes, and surface roughness occurred at the inner surface of the sectioned drilled hole. The quality of the drilled holes was compared based on the delamination factor and the surface roughness, as analyzed by the 3D optical surface profiles.publishedVersio
Assessment of Rangeland Degradation in New Mexico Using Time Series Segmentation and Residual Trend Analysis (TSS-RESTREND)
Rangelands provide significant socioeconomic and environmental benefits to humans. However, climate variability and anthropogenic drivers can negatively impact rangeland productivity. The main goal of this study was to investigate structural and productivity changes in rangeland ecosystems in New Mexico (NM), in the southwestern United States of America during the 1984-2015 period. This goal was achieved by applying the time series segmented residual trend analysis (TSS-RESTREND) method, using datasets of the normalized difference vegetation index (NDVI) from the Global Inventory Modeling and Mapping Studies and precipitation from Parameter elevation Regressions on Independent Slopes Model (PRISM), and developing an assessment framework. The results indicated that about 17.6% and 12.8% of NM experienced a decrease and an increase in productivity, respectively. More than half of the state (55.6%) had insignificant change productivity, 10.8% was classified as indeterminant, and 3.2% was considered as agriculture. A decrease in productivity was observed in 2.2%, 4.5%, and 1.7% of NM's grassland, shrubland, and ever green forest land cover classes, respectively. Significant decrease in productivity was observed in the northeastern and southeastern quadrants of NM while significant increase was observed in northwestern, southwestern, and a small portion of the southeastern quadrants. The timing of detected breakpoints coincided with some of NM's drought events as indicated by the self-calibrated Palmar Drought Severity Index as their number increased since 2000s following a similar increase in drought severity. Some breakpoints were concurrent with some fire events. The combination of these two types of disturbances can partly explain the emergence of breakpoints with degradation in productivity. Using the breakpoint assessment framework developed in this study, the observed degradation based on the TSS-RESTREND showed only 55% agreement with the Rangeland Productivity Monitoring Service (RPMS) data. There was an agreement between the TSS-RESTREND and RPMS on the occurrence of significant degradation in productivity over the grasslands and shrublands within the Arizona/NM Tablelands and in the Chihuahua Desert ecoregions, respectively. This assessment of NM's vegetation productivity is critical to support the decision-making process for rangeland management; address challenges related to the sustainability of forage supply and livestock production; conserve the biodiversity of rangelands ecosystems; and increase their resilience. Future analysis should consider the effects of rising temperatures and drought on rangeland degradation and productivity.Peer reviewe
Exploration of Mechanical Properties of Enset–Sisal Hybrid Polymer Composite
Enset and sisal fibers are among the most widely used reinforcement to fabricate natural fiber-based composite materials. Hand lay-up techniques were employed in this study to fabricate enset–sisal (E/S) hybrid fiber composite with volume ratios of 100/0, 75/25, 50/50, 25/75, and 0/100 and constant polyester resin. The tensile, flexural, impact strength, water absorption and morphological properties of the fabricated composite were investigated experimentally. The effects of hybridization to volume ratio were determined and the results show that hybrid composites excel in mechanical properties, compared with single composites. For better mechanical properties, the enset fiber has been hybridized with sisal fiber. Tensile and flexural strengths were enhanced by 47.3% and 41.03%, respectively, at 50/50 E/S volume ratio compared with 100/0 E/S composite. The impact strength of sisal fiber composite was improved by adding enset fiber in the composites. The inherent benefits and limitations of these two fibers were balanced out by each other in a positive way. While sisal fiber helped the composite intermesh of tensile, flexural, and reduction of water absorption, enset ensured impact strength. Morphological analysis was carried out in order to observe the fracture behavior and fiber pull-out of the samples by means of scanning electron microscopy.publishedVersio
Hepatotoxicity and Associated Risk Factors in Hiv-Infected Patients Receiving Antiretroviral Therapy at Felege Hiwot Referral Hospital, Bahirdar, Ethiopia
Background: In Human Immunodeficiency Virus (HIV) infected patients on antiretroviral treatment (ART), hepatotoxicity is life threatening. Its outcome may lead to liver failure and death. This study was conducted to determine the rate and determinants of elevated alanine amino transferase (ALT) (referred as >40IU/L for both males and females).Methods: A cross sectional study was conducted on HIV infected individuals who are on ART and suspected of drug resistance at Felege Hiwot Referral Hospital, Bahir Dar from July to December 2012. Venous bloods were collected from each patient and processed parallely to determine ALT, number of HIV RNAs, CD4 and CD8 T cells count, anti hepatitis C virus (HCV) and hepatitis B surface antigen.Results: Out of 269 HIV infected patients receiving ART, 32% were confirmed of grades 1-4 levels of elevated ALT. The rate of severe hepatotoxicity (grade 3 and 4) was 1.84%. Patients with increased CD8 T cell counts (P=0.011; AOR=1.82; CI: 1.12 - 2.54), alcohol over use (P=0.014; AOR = 1.23; CI: 1.36- 3.29) and detectable HIV-1 RNA copies (P=0.015; AOR=2.07; CI: 1.15-3.74) independently predicts the elevation of ALT.Conclusions: In HIV infected patients on ART, extreme elevations of ALT were infrequent but minor elevations were common so that patient-linked variables such as use of alcohol intake must be taken in to account for better clinical management of ART patients. The role of active HCV co-infection on the treatment outcome of ART should be further studied.Key words: ALT, HIV, ART, Bahir Dar, Ethiopi
Modeling the water budget of the Upper Blue Nile basin using the JGrass-NewAge model system and satellite data
The Upper Blue Nile basin is one of the most data-scarce regions in developing countries, and hence the hydrological information required for informed decision making in water resource management is limited. The hydrological complexity of the basin, tied with the lack of hydrometeorological data, means that most hydrological studies in the region are either restricted to small subbasins where there are relatively better hydrometeorological data available, or on the whole-basin scale but at very coarse timescales and spatial resolutions. In this study we develop a methodology that can improve the state of the art by using available, but sparse, hydrometeorological data and satellite products to obtain the estimates of all the components of the hydrological cycle (precipitation, evapotranspiration, discharge, and storage). To obtain the water-budget closure, we use the JGrass-NewAge system and various remote sensing products. The satellite product SM2R-CCI is used for obtaining the rainfall inputs, SAF EUMETSAT for cloud cover fraction for proper net radiation estimation, GLEAM for comparison with NewAge-estimated evapotranspiration, and GRACE gravimetry data for comparison of the total water storage amounts available in the whole basin. Results are obtained at daily time steps for the period 1994–2009 (16 years), and they can be used as a reference for any water resource development activities in the region. The overall water-budget analysis shows that precipitation of the basin is 1360 ± 230 mm per year. Evapotranspiration accounts for 56 % of the annual water budget, runoff is 33 %, storage varies from −10 to +17 % of the water budget
Intention toward condom use and its associated factors among students of Debre Work Senior Secondary and Preparatory School, East Gojjam Zone, Amhara Region, Ethiopia
Objective: The main aim of this research was to investigate the students’ intention toward condom use and associated factors among students in Debre Work Secondary and Preparatory School, 2015. Methods: A survey was carried out in the high school and the preparatory school. The selfadministered semistructured questionnaire was distributed to 422 students. Systematic sampling techniques were employed to each class. Data were entered and analyzed by using SPSS version 20.0 software. Descriptive and analytical data analysis and presentation were used. Logistic regression model was used to check independent associations. Result: Most (80.8%) of the respondents were not married. More than half (53.0% and 52.3%) of the respondents had low perceived benefit and low perceived self-efficacy of using condom. About 46.79% of respondents had an interest in using condoms and the rest had no intention. Males were 1.96 times more likely to have intention to use condom compared to females (adjusted odds ratio [AOR], 95% confidence interval [CI] 1.96 [1.29, 2.99]). When the intention to use condoms was compared, married respondents were 2.41 times more likely than those who were not married (AOR, 95% CI 2.41 [1.41, 4.14]). Intention to use condoms among respondents who had high perceived benefit of using condom were 1.57 times more compared to those who had low perceived benefit of using condom (AOR, 95% CI 1.57 [1.03, 2.39]). Intention to use condoms among those who had high perceived self-efficacy on condom use was 4.37 times higher compared to those who had low perceived self-efficacy (AOR, 95% CI 4.37 [2.85, 6.71]). Conclusion: The level of intention to use condoms among students of Debre Work Senior Secondary and Preparatory School was low. Sex, current marital status, perceived benefit of using condom, and perceived self-efficacy on condom use were the most positive contributing factors for intention to condom use.Habtamu Abera, Fanta Tamiru, Getiye Dejenu Kibre
An assessment of integrated watershed management in Ethiopia
Sustainable participatory watershed management is an approach promoted by the Ethiopian government to restore natural resources and agricultural productivity across the country. This comparative study between six watershed programs shows that this approach increases farmers’ food security and incomes (around 50% on average), as well as their resilience to drought and other climate shocks. However, the study also confirms that the nature and scale of impact can vary significantly between watershed programs. The success of watershed management depends on multiple factors from the hydrological profile of the watershed to the local social and economic environment. Tailoring watershed interventions to the local context, associating conservation and livelihoods activities, and providing further financial and technical support to watershed committees are among the recommendations of this paper
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