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Search Results: 1 - 10 of 67 matches for " Tigist Shiferaw "
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Long Term Effects of Radiation-Induced Osteonecrosis of the Pelvis Caused Complete Failure of Total Hip Arthroplasty  [PDF]
Tigist Wodaje, Per Wretenberg
Surgical Science (SS) , 2012, DOI: 10.4236/ss.2012.37074
Abstract: This case report describe severe osteonecrosis of the pelvis more than 30 years after radiation due to ovarian cancer. As orthopedic surgeon it is important to ask about previous radiation to the pelvis in case of total hip arthroplasty and also to perform CT in unclear cases.
Native Woody Plants Diversity and Density under Eucalyptus camaldulensis Plantation, in Gibie Valley, South Western Ethiopia  [PDF]
Shiferaw Alem, Jindrich Pavlis
Open Journal of Forestry (OJF) , 2012, DOI: 10.4236/ojf.2012.24029
Abstract: The aim of the study was to assess the impact of E. camaldulensis plantation established in a semi-arid area on native woody plants diversity and density. Nested quadrant plot design, having an area of 15 m × 15 m used to collect data. Totally, 37 species at the plantation and 30 species at the native woodland, belonging to 24 families, identified. Species diversity (H′) was 1.57 at the plantation and 2.09 at the woodland forest. As for density of understory woody plants (height ≥ 1 m) the plantation forest harbored 6, 604 stems/ha while the native woodland had 7, 347 stems/ha. Seedling density (height < 1 m) at the native woodland and at the plantation there were 11,436 stems/ha and 8,865 stems/ha, respectively. The similarity of woody species composition between the woodland forest and the plantation was low. However, in terms of autochthonous tree seed bank availability, authentic hypothesis seems to prove that if clear-cut patches replanted by introduced species that do not exceed 5 ha, they still significantly favour original forest regeneration and composition in a semi-arid area and surprisingly favors the regeneration of Dodonaea angustifolia and other native species important for soil conservation, timber, bee forage and medicinal use.
In Vitro Callus Induction and Shoot Regeneration from Leaf Explants of Glinus lotoides (L.)—An Important Medicinal Plant  [PDF]
Shiferaw Teshome, Tileye Feyissa
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.69132
Abstract: G. lotoides L. is a threatened plant that is frequently harvested for medicinal purpose. However, its distribution in the world is limited because of short period of seed viability and poor seed germination. The objective of this study was to develop in vitro propagation protocol for G. lotoides through callus induction. For callus induction, different concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid), NAA (α-naphthalene acetic acid) and BAP (6-benzyl amino purine) were used. Seeds were sown on growth regulator-free MS medium and shoots from the in vitro germinated seedlings were excised and cultured on MS medium containing 0.5 mg/l BAP. Young leaves from these shoots were used as explant for callus induction and shoot regeneration. Maximum callus induction (100%) was observed on medium containing 2,4-D (0.5, 2.0, 3.5 mg/l) or NAA (2.0, 2.5 mg/l) in combination with 0.5 mg/l BAP. However, 2,4-D was the best in overall callus induction. The highest regeneration (20%) frequency was achieved on the medium containing 0.5 mg/l BAP. Highest number of shoot (2.83 ± 1.22) and shoot length (2.16 ± 0.87 cm) per explant were obtained in the presence of 0.25 mg/l BAP + 0.5 mg/l KIN (Kinetin). In shoot multiplication media, maximum mean (6.43 ± 0.87) of shoot was observed on MS medium containing 0.5 mg/l BAP. The best shoot length (1.70 ± 0.14 cm) was recorded on control medium. The highest (95%), maximum root number (14.10 ± 1.47) and root length (1.01 ± 0.10 cm) were obtained on a medium supplemented with 1.5 mg/l Indole-3-butyric acid (IBA). All the plants (100%) were survived after acclimatization in greenhouse. The present study can be useful for callus induction and indirect shoot regeneration form G. lotoides.
Children Who Received PCV-10 Vaccine from a Two-Dose Vial without Preservative Are Not More Likely to Develop Injection Site Abscess Compared with Those Who Received Pentavalent (DPT-HepB-Hib) Vaccine: A Longitudinal Multi-Site Study
Yemane Berhane, Alemayehu Worku, Meaza Demissie, Neghist Tesfaye, Nega Asefa, Worku Aniemaw, Berhe Weldearegawi, Yigzaw Kebede, Tigist Shiferaw, Amare Worku, Lemessa Olijira, Behailu Merdekios, Yemane Ashebir, Takele Tadesse, Yadeta Dessie, Solomon Meseret, Gestane Ayele
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0097376
Abstract: Background The single dose pneumonia ten-valent vaccine has been widely used and is highly efficacious against selected strains Streptococcus pneumonia. A two-dose vial without preservative is being introduced in developing countries to reduce the cost of the vaccine. In routine settings improper immunization practice could result in microbial contamination leading to adverse events following immunization. Objective To monitor adverse events following immunization recommended for routine administration during infancy by comparing the rate of injection-site abscess between children who received PCV-10 vaccine and children who received the Pentavalent (DPT-HepB-Hib) vaccine. Methods A longitudinal population-based multi-site observational study was conducted between September 2011 and October 2012. The study was conducted in four existing Health and Demographic Surveillance sites run by public universities of Abraminch, Haramaya, Gondar and Mekelle. Adverse events following Immunization were monitored by trained data collectors. Children were identified at the time of vaccination and followed at home at 48 hour and 7 day following immunization. Incidence of abscess and relative risk with the corresponding 95% Confidence Intervals were calculated to examine the risk difference in the comparison groups. Results A total of 55, 268 PCV and 37, 480 Pentavalent (DPT-HepB-Hib) vaccinations were observed. A total of 19 adverse events following immunization, 10 abscesses and 9 deaths, were observed during the one year study period. The risk of developing abscess was not statistically different between children who received PCV-10 vaccine and those received Pentavalent (RR = 2.7, 95% CI 0.576–12.770), and between children who received the first aliquot of PCV and those received the second aliquot of PCV (RR = 1.72, 95% CI 0.485–6.091). Conclusion No significant increase in the risk of injection site abscess was observed between the injection sites of PCV-10 vaccine from a two-dose vial without preservative and pentavalent (DPT-HepB-Hib) vaccine in the first 7 days following vaccination.
An Efficient Direct Method to Solve the Three Dimensional Poisson’s Equation  [PDF]
Alemayehu Shiferaw, Ramesh Chand Mittal
American Journal of Computational Mathematics (AJCM) , 2011, DOI: 10.4236/ajcm.2011.14035
Abstract: In this work, the three dimensional Poisson’s equation in Cartesian coordinates with the Dirichlet’s boundary conditions in a cube is solved directly, by extending the method of Hockney. The Poisson equation is approximated by 19-points and 27-points fourth order finite difference approximation schemes and the resulting large algebraic system of linear equations is treated systematically in order to get a block tri-diagonal system. The efficiency of this method is tested for some Poisson’s equations with known analytical solutions and the numerical results obtained show that the method produces accurate results. It is shown that 19-point formula produces comparable results with 27-point formula, though computational efforts are more in 27-point formula.
Fast Finite Difference Solutions of the Three Dimensional Poisson’s Equation in Cylindrical Coordinates  [PDF]
Alemayehu Shiferaw, R. C. Mittal
American Journal of Computational Mathematics (AJCM) , 2013, DOI: 10.4236/ajcm.2013.34045
Abstract:

In this work, the three-dimensional Poisson’s equation in cylindrical coordinates system with the Dirichlet’s boundary conditions in a portion of a cylinder for is solved directly, by extending the method of Hockney. The Poisson equation is approximated by second-order finite differences and the resulting large algebraic system of linear equations is treated systematically in order to get a block tri-diagonal system. The accuracy of this method is tested for some Poisson’s equations with known analytical solutions and the numerical results obtained show that the method produces accurate results.

High Accurate Fourth-Order Finite Difference Solutions of the Three Dimensional Poisson’s Equation in Cylindrical Coordinate  [PDF]
Alemayehu Shiferaw, Ramesh Chand Mittal
American Journal of Computational Mathematics (AJCM) , 2014, DOI: 10.4236/ajcm.2014.42007
Abstract:

In this work, by extending the method of Hockney into three dimensions, the Poisson’s equation in cylindrical coordinates system with the Dirichlet’s boundary conditions in a portion of a cylinder for is solved directly. The Poisson equation is approximated by fourth-order finite differences and the resulting large algebraic system of linear equations is treated systematically in order to get a block tri-diagonal system. The accuracy of this method is tested for some Poisson’s equations with known analytical solutions and the numerical results obtained show that the method produces accurate results.

Poverty and natural resource management in the semi-arid tropics: revisiting challenges and conceptual issues
Bekele Shiferaw
Journal of SAT Agricultural Research , 2006,
Abstract: As many of the poor in developing countries depend on agriculture for their livelihoods, agricultural development is widely regarded as a viable strategy for reducing poverty and conservation of the natural resources base. This recognition has necessitated a wide range of interventions to increase the productivity of agriculture and enhance food security in poor areas. Despite such efforts and the increased momentum towards globalization, along with increasing scarcity of land and water resources, poverty and resource degradation have increased in some marginalized areas, especially in sub-saharan Africa. A number of studies in recent times have postulated a self-reinforcing downward spiral between poverty, population pressure, and natural resource degradation. These interlinkages seem to be valid for certain arid and semi-arid areas with fragile and marginal environments where biophysical and socioeconomic constraints limit investment opportunities. With emphasis in semi-arid rainfed areas, this study examines the livelihood-environmental linkages in light of the existing theories and empirical evidence; synthesizes major lessons; suggests research and policy implications; and advances a more holistic and interdisciplinary analytical framework for understanding the most limiting structural constraints, farmer decision behavior, and investment strategies.
Analysis of Watershed Attributes for Water Resources Management Using GIS: The Case of Chelekot Micro-Watershed, Tigray, Ethiopia  [PDF]
Tesfaye Gebre, Tigist Kibru, Samuale Tesfaye, Gebeyehu Taye
Journal of Geographic Information System (JGIS) , 2015, DOI: 10.4236/jgis.2015.72015
Abstract: This study identified the importance of watershed attributes for water resource management using ArcGIS software, ASTER DEM and satellite images for the Chelekot micro-watershed, Tigray, Ethiopia. The study also evaluate the different hydrological parameters which are significant for the water resource management within the micro-watershed and finds the alternative solutions for water harvesting in the study area through the introduction of suitable soil and water conservation structures based on the finding. Principal watershed attributes including drainage pattern, topographic parameters, land use types, and soil types were evaluated and interpreted for the study micro-watershed. ArcGIS software was used for the computation, delineation of the boundary and morphometric analysis of the micro-watershed using topographical maps and ASTER DEM data. Results indicate that the micro-watershed has classified as a dendritic pattern with stream orders ranging from first to fifth order. The micro-watershed has homogeneity in texture and lack of structural control of surface flow. The drainage density is medium which indicates the area contains soils with medium infiltration rates and moderate relief. Drainage texture, stream frequency and the form factor of the micro-watershed are 4.1, 1.7 and 0.4 respectively. The bifurcation ratio of the micro-watershed ranges from 1 to 4.5 and the elongation ratio is 0.7 which reveals that the micro-watershed belongs to the less elongated shaped micro-watershed category. The mean bifurcation ratio of the whole micro-watershed is 3.3 indicating that the drainage pattern is not greatly influenced by geological structures. The micro-watershed land covers includes: cultivated land (75.8%), settlement and open land (10.5%), shrubs and plantation (13.2%), and water body (0.4%). The major soil types are Vertisol (58%), Camisole (32%), Regosol (9.5%) and Luvisol (0.7%). The textural classes are clay (5%), silty clay (22%), clay loam (17%), sandy loam (21%) and loam (35%) based on the soil textural map of the micro-watershed. Our results revealed that using GIS and ASTER DEM data based watershed morphometric analysis and hydrological evaluation at watershed scale is more applied and precise compared to other available techniques.
Genetic Variation for Grain Yield and Yield Related Traits in Tef [Eragrostis tef (Zucc.)Trotter] under Moisture Stress and Non-Stress Environments  [PDF]
Wondewosen Shiferaw, Alemayehu Balcha, Hussen Mohammed
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.38124
Abstract: Tef [Eragrostis tef (Zucc.)Trotter] is an ancient and major cereal crop in Ethiopia. Increasing tef grain yield partly requires developing cultivars that are adapted to drought stress environment. An experiment was carried out using 18 tef genotypes grown during September to December, 2010, under two water supply environments (stress during grain filling period, and non-stress) to identify genetic variation, heritability and correlations of grain yield and yield related traits. Broad-sense heritability values under respective stress and non-stress environments were grain yield (g/m2) 0.80 and 0.89, total biomass (g/m2) 0.89 and 0.73, harvest index 0.69 and 0.79, panicle weight (g/plant) 0.93 and 0.92, and seed weight (g/plant) 0.96 and 0.86. The correlations of grain yield under respective stress and non-stress environments were total biomass rp = 0.64, rg = 0.70, and rp = 0.48, rg = 0.56, harvest index rp = 0.70, rg = 0.64, and rp = 0.87, rg = 0.90, panicle weight rp = 0.98, rg = 1.00, and rp = 0.96, rg = 1.00, and seed weight/plant rp = 0.98, rg = 1.00, and rp = 0.90, rg = 1.00. The present experiment showed that either grain yield per se, or seed weight/plant could be used to improve grain yield under stress and non-stress environments.
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