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Changes in land use/cover mapped over 80 years in the Highlands of Northern Ethiopia

Journal of Geographical Sciences 2018年第10期28卷 1538-1559页

作者： ETEFA Guyassa Amaury FRANKL Sil LANCKRIET BIADGILGN Demissie gebreyohannes zenebe AMANUEL zenebe Jean POESEN Jan NYSSEN Department of Geography Ghent University Department of Land Resources Management and Environmental Protection Mekelle University Research Foundation Flanders (FWO) Department of Geography and Environmental Studies Mekelle University Institute of Geo-information and Earth Observation Sciences Mekelle University Division of Geography Department of Earth and Environmental Sciences

Despite many studies on land degradation in the Highlands of Northern Ethiopia, quantitative information regarding long-term changes in land use/cover(LUC) is rare. Hence, this study aims to investigate the LUC changes in the Geba catchment(5142 km2), Northern Ethiopia, over 80 years(1935–2014). Aerial photographs(APs) of the 1930 s and Google Earth(GE) images(2014) were used. The point-count technique was utilized by overlaying a grid on APs and GE images. The occurrence of cropland, forest, grassland, shrubland, bare land, built-up areas and water body was counted to compute their fractions. A multivariate adaptive regression spline was applied to identify the explanatory factors of LUC and to create fractional maps of LUC. The results indicate significant changes of most types, except for forest and cropland. In the 1930 s, shrubland(48%) was dominant, followed by cropland(39%). The fraction of cropland in 2014(42%) remained approximately the same as in the 1930 s, while shrubland significantly dropped to 37%. Forests shrank further from a meagre 6.3% in the 1930 s to 2.3% in 2014. High overall accuracies(93% and 83%) and strong Kappa coefficients(89% and 72%) for point counts and fractional maps respectively indicate the validity of the techniques used for LUC mapping.

关键词： fractional map Google Earth land use/cover multivariate adaptive regression Italian aerial photographs

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Applicability of Gravity Separation Method on the Ashashire Gold Ore Deposit from Benishangul Gumuz Region, Western Ethiopia

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International Journal of Nonferrous Metallurgy 2024年第2期11卷 21-31页

作者： Misganu Kabeta Mulugeta Sisay Cheru Goitom gebreyohannes Berhe School of Chemical and Bio Engineering Center for Ethio-Mines Development AAiT Addis Ababa University Addis Ababa Ethiopia Mineral Industry Development Institute Ministry of Mines Addis Ababa Ethiopia School of Materials Science and Engineering Jimma Institute of Technology Jimma University Jimma Ethiopia College of Natural and Computational Sciences Mekelle University Mekelle Ethiopia

The study was conducted to determine the applicability of gravity separation method on the Ashashire gold ore deposit Benishangul gumuz region, western Ethiopia. The Ashashire composite was produced to provide sufficient mass for this study and experiment, including sample preparation, mineralogical analysis of gold and associated elements, gravity concentration, and data interpretation and analysis. During the study, a grind optimization was conducted on the composites sample with varying grind size to evaluate the effect of grind size on gold recovery. The ore was moderately ground to the standard grind size of 80%, passing 106 µm, 75 µm, 53 µm and this nominal size was selected for the preliminary assessment for concentration optimization for this deposit. The gravity testing comprised three-stage concentration using Knelson concentrator. High recovery of gold from the gravity concentrates was achieved from the second gravity concentration. Based on the laboratory experimental result analysis, a grind size of P80 75 µm is selected as optimal size for the Ashashire gold deposit. Increasing the grind size from P80 of 75 µm to 106 µm decreases the recovery rate from 75% to 54%, or decreasing the grind size from P80 of 75 µm to 53 µm decreases the gold recovery rate to 37%. The native gold grain in the ores is mostly associated with quartz and fine gold is closely associated with pyrite. According to analysis of the fire assay, chemical, and mineralogical data, only gold and telluride is commercially valuable elements in the ores. Predominantly gold was occurred in the native form of Au-Te. The sample subjected to gravity separation assayed about 2.6 g/t Au.

关键词： Ore Gangue Ashashire Gravity Method Gold Telluride Concentration Knelson

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Alternative beneficiation of tantalite and removal of radioactive oxides from Ethiopian Kenticha pegmatite–spodumene ores

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International Journal of Minerals,Metallurgy and Materials 2017年第7期24卷 727-735页

作者： Berhe Goitom gebreyohannes Velázquez del Rosario Alberto Abubeker Yimam Girma Woldetinsae Bogale Tadesse School of Materials Science and Engineering Jimma Institute of Technology Jimma University P.O. Box 378 Jimma Ethiopia Chemistry Department College of Natural and Computational Science Mekelle University P.O. Box 823 Mekelle Ethiopia School of Chemical and Bio Engineering AAiT Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia Research and Development Directorate Federal Democratic Republic of Ethiopia Ministry of Mines Petroleum and Natural Gas P.O. Box 486 Addis Ababa Ethiopia Department of Mining Engineering and Metallurgical Engineering Western Australian School of Mines Curtin University Egan St Kalgoorlie WA 6430 Australia

The beneficiation methods for Ethiopian Kenticha pegmatite–spodumene ores were assessed through mineralogical and quantitative analyses with X-ray diffraction（XRD） and energy-dispersive X-ray fluorescence（EDXRF）. The tantalite in the upper zone of the Kenticha pegmatite–spodumene deposit is 58.7wt% higher than that in the inner zone. XRD analysis revealed that the upper zone is dominated by manganocolumbite, whereas the inner zone is predominantly tantalite-Mn. Repeated cleaning and beneficiation of the upper-zone ore resulted in concentrate compositions of 57.34wt% of Ta_2O_5 and 5.41wt% of Nb_2O_5. Washing the tantalite concentrates using 1vol% KOH and 1 M H_2SO_4 led to the removal of thorium and uranium radioactive oxides from the concentrate. The findings of this study suggest that the beneficiation and alkaline washing of Kenticha pegmatite–spodumene ores produce a high-grade export-quality tantalite concentrate with negligible radioactive oxides.

关键词： beneficiation manganocolumbite pegmatite-spodumene radioactive oxides tantalite

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Isolation and characterization of potential antibiotic producing actinomycetes from water and sediments of Lake Tana,Ethiopia

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Asian Pacific Journal of Tropical Biomedicine 2013年第6期3卷 426-435页

作者： Gebreselema gebreyohannes Feleke Moges Samuel Sahil Nagappan Raja Department of Biology Faculty of Natural and Computational SciencesPost Box 196University of GondarEthiopia Department of Medical Microbiology College of Medical and Health SciencesPost Box 196University of GondarEthiopia

Objective:To isolate,evaluate and characterize potential antibiotic producing actinomycetes from water and sediments of Lake Tana,***:A total of 31 strains of actinomycetes were isolated and tested against Gram positive and Gram negative bacterial strains by primary *** the primary screening.11 promising isolates were identified and subjected to solid state and submerged state fermentation methods to produce crude *** fermented biomass was extracted by organic solvent extraction method and tested against bacterial strains by disc and agar well diffusion *** isolates were characterized by using morphological,physiological and biochemical ***:The result obtained from agar well diffusion method was belter than disc diffusion *** crude extract showed higher inhibition zone against Gram positive bacteria than Cram negative ***-way analysis of variance confirmed most of the crude extracts were statistically significant at 95%confidence *** minimum inhibitor)concentration and minimum bactericidal concentration of crude extracts were 1.65 mg/mL and 3.30 mg/mL against Staphylococcus aureus,and 1.84 mg/mL and 3.80 mg/mL against Escherichia coli *** growth of aerial and substrate mycelium varied in different culture media *** of the isolates were able to hydrolysis starch and urea:able to survive at 5%concentration of sodium chloride:optimum temperature for their growth was 30°***:The results of the present study revealed that freshwater actinomycetes of Luke Tana appear to have immense potential as a source ol antibacterial compounds.

关键词： Actinomycetes Solid state fermentation Submerged state fermentation Disc diffusion method Agar well diffusion method Crude extracts Antibiotics Antibacterial activity

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Full Frontal Car Crash Simulation Using LS-DYNA

Full Frontal Car Crash Simulation Using LS-DYNA

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作者： gebreyohannes MICHAEL OKUBU 湖南大学

学位级别：硕士

由于汽车零部件的设计和选择不当,每年都会有许多汽车碰撞安全事故发生。本论文运用有限元方法,通过选择材料和改变部件厚度的方法对汽车前部构件进行优化以提高整车耐撞性,进而降低人体损伤程度。汽车的安全性能对于汽车工业来说是非... 详细信息

由于汽车零部件的设计和选择不当,每年都会有许多汽车碰撞安全事故发生。本论文运用有限元方法,通过选择材料和改变部件厚度的方法对汽车前部构件进行优化以提高整车耐撞性,进而降低人体损伤程度。汽车的安全性能对于汽车工业来说是非常重要的。车辆结构物理碰撞试验的复杂性使得结构的设计优化过程变得非常复杂。但是,具有非线性特性的车辆结构的耐撞性仿真使得直接对车身结构件进行优化变为可能。除此之外,有限元仿真方法还可以节省时间及成本。在碰撞中,车辆前部构件吸能最多。采用HyperMesh和LS-DYNA软件,本文进行了汽车正面碰撞仿真,并对其中的重要吸能构件进行分析和优化,以提高其能量吸收能力。碰撞吸能性能是评价汽车碰撞安全性的重要指标之一,本文对其结构性能和结构优化特性进行了研究。首先基于Hypermesh和LS-DYNA软件建立了整车仿真模型,仿真结果表明,需要对前部构件进行改进,以满足工程要求。然后基于整车模型,对保险杠、纵梁和其他能量吸收部件进行了优化并分析了仪表板的侵入量,为保障乘员舱乘客的安全预留出一定的空间。本文对优化之后的模型进行100%正面碰撞仿真,通过分析B柱加速度,以及部件变形吸能情况来验证优化是否符合要求。最终,将建立好的整车模型提交LS-DYNA软件进行求解计算,仿真结果在Hyperworks软件中输出。本文比较了模型优化前后B柱加速度以及部件变形量情况,并验证了模型优化是否符合C-NCAP法规要求。

关键词：优化汽车碰撞 Hypermesh LS-DYNA C-NCAP 吸能量

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The MET Analysis of Yield Performance of Advanced Sorghum [<i>Sorghum Bicolor</i>(L.) Moench] Lines under Moisture Stress Areas Using Spatial Analysis

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American Journal of Plant Sciences 2020年第10期11卷 1618-1631页

作者： Kidanemaryam Wagaw Amare Seyoum Taye Tadesse Adane gebreyohannes Amare Nega Diriba Tadesse Ethiopian Institute of Agricultural Research Melkassa Agricultural Research Center Adama Ethiopia Ethiopian Institute of Agricultural Research Head Quarter Addis Ababa Ethiopia

Sorghum is one of the most widely cultivated cereal crops in Ethiopia which is grown for food and feed uses. It’s far an indigenous crop that’s grown in incredibly diverse environments of getting diverse water strain, soil fertility, and temperature situations. Trait of sorghum varieties tolerant to drought and producing desirable grain yield at the same time as addressing the biomass requirement is one of the techniques within the sorghum breeding program to the dry lowland surroundings so one can feed the growing population in Ethiopia. A total of 126 superior early maturing sorghum elite lines had been evaluated through along with recently released popular trendy check Melkam and Argiti to estimate the grain yield and stability of overall performance throughout the testing environments. Based on the overall performance of grain yield, flowering time, plant height, and the stability of grain yield genotype ETSC14501-2-2 and 14MWLSDT7196 become top ranked followed by genotype 14MWLSDT7176, 14MWLSDT7241 and 13MWF6#6037 which could be a capability candidate for production to the target environments. The varieties had better grain yield performance and stability across the environment, which may be used as capacity parental lines for genetic improvement in the sorghum improvement program. Finally based on the presented result on early maturing variety ETSC14501-2-2 with the pedigree of Redswazi/Meko-1 identified and registered for variety verification across locations on stations and on farms to confirm the stability and preference by farmers with their own farming practices.

关键词： Heritability Stability META Elite Lines Correlation Spatial Analysis

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Treatment outcomes of visceral leishmaniasis in Ethiopia from 2001 to 2017:a systematic review and meta-analysis

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Infectious Diseases of Poverty 2018年第1期7卷 1144-1152页

作者： Eyob Alemayehu gebreyohannes Akshaya Srikanth Bhagvathula Tadesse Melaku Abegaz Mohammed Assen Seid Department of Clinical Pharmacy College of Medicine and Health SciencesUniversity of GondarGondarEthiopia

Background:Ethiopia has the highest number of visceral leishmaniasis(VL)cases after Sudan in Sub-Saharan ***,there was lack of comprehensive data on VL treatment outcome despite the huge burden of the diseases in the ***,we aimed to perform a systematic review and meta-analysis on this topic to obtain stronger evidence on treatment outcomes of VL from the existing literature in ***:The Cochrane guidelines to conduct meta-analysis following the Preferred Reporting Items for Systematic review and Meta-Analysis statement was used to conduct a computerized systematic search of the PubMed,Google Scholar,and ScienceDirect *** effects model was used to combine studies showing heterogeneity of Cochrane Q P*** outcomes were assessed at end of treatment and at 6 months *** analyses were performed on treatment outcomes based on the different antileishmanial treatment options and patients’HIV ***:Fifteen studies were included in the final *** end of treatment,an overall treatment success rate of 82.6%was *** 6 months follow-up,the overall treatment success rate was 72.2%.For patients treated with sodium stibogluconate(SSG),the treatment success rates at the end of treatment and at six-month follow-up were 81.5%and 80.7%,*** doses of liposomal-amphotericin B(L-AMB)had treatment success rates of 96.7 and 71-100%at the end of treatment and at 6 months follow-up,*** combination of SSG with paromomycin(PM)gave treatment success rates of up to 90.1%at the end of ***-infected individuals were found to have a higher mortality(odds ratio=4.77,95%CI:1.30-17.43,P=0.009)rate at 6 months ***:SSG alone has shown lower treatment efficacy in the management of VL when compared to combination of SSG with PM and multiple doses of *** combination of SSG with PM gave good treatment success rates with shorter duration of treatm

关键词： Visceral leishmaniasis Sodium stibogluconate Amphotericin b Paromomycin Treatment Success Mortality HIV/AIDS Ethiopia

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高效液相色谱法测定生物样品中3PO的方法建立与验证（英文）

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药物分析杂志 2013年第11期33卷 1873-1876,1886页

作者： Yemarshet K.gebreyohannes 王旭 Getu Kahsay Weldu Erwin Adams Ann Van Schepdael 荷语天主教鲁汶大学药学院药物分析实验室

目的:建立并验证用于大鼠血清、脑脊液、大脑和脊髓中3-(3-吡啶)-1-(4-吡啶)-2-丙烯-1-酮(3PO)含量测定的HPLC-UV法。方法:样品处理使用蛋白沉淀的方法;色谱条件:色谱柱为Chromolith RP-18e(100 mm×4.6 mm),流动相A为乙腈-水(2.5∶97.5... 详细信息

目的:建立并验证用于大鼠血清、脑脊液、大脑和脊髓中3-(3-吡啶)-1-(4-吡啶)-2-丙烯-1-酮(3PO)含量测定的HPLC-UV法。方法:样品处理使用蛋白沉淀的方法;色谱条件:色谱柱为Chromolith RP-18e(100 mm×4.6 mm),流动相A为乙腈-水(2.5∶97.5,v/v)添加0.1%TFA,流动相B为乙腈添加0.1%TFA,梯度洗脱[0～2.3 min,0%B→100%B(线性梯度);2.3～2.6 min,100%B(等度);2.6～2.7 min,100%B→0%B(线性梯度);2.7～5 min,0%B(等度)],流速2 mL·min-1,检测波长304 nm,进样量10μL。结果:大鼠的血清、脑脊液、大脑和脊髓中内源性物质不干扰3PO的测定,在上述4种基质中,该方法的检测限分别为0.2、0.1、0.1、0.1μg·mL-1;定量限分别为0.8、0.2、0.5、0.5μg·mL-1;线性范围分别为3～150、0.3～150、0.9～150、0.6～150μg·mL-1,相关系数均大于0.999;高、低浓度的回收率均在79.9%～100.3%的范围内;方法重复性(n=5)的RSD均大于0.9%。结论:建立的方法简单,线性范围宽,且选择性、耐用性均佳。

关键词：高效液相色谱生物分析 3PO 3-(3-吡啶)-1-(4-吡啶)-2-丙烯-1-酮

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Distinguishing of Stable Genotypes and Mega Environment for Grain Yield Performance of Sorghum [<i>Sorghum bicolor</i>(L.) Moench] Genotypes Using Spatial Analysis

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American Journal of Plant Sciences 2021年第3期12卷 417-431页

作者： Kidanemaryam Wagaw Amare Seyoum Taye Tadesse Amare Nega Adane gebreyohannes Tamirat Bejiga Sewmehon Siraw Hailemariam Solomon Daniel Nadew Meron Bogale Melkassa Agricultural Research Center Ethiopian Institute of Agricultural Research Adama Ethiopia Crop Research Directorate Ethiopian Institute of Agricultural Research Addis Ababa Ethiopia Department of Cellular Microbial and Molecular Biology College of Natural Science Addis Ababa University Addis Ababa Ethiopia School of Agricultural Earth and Environmental Sciences College of Agriculture Engineering and Science University of KwaZulu-Natal Pietermaritzburg South Africa School of Plant Sciences College of Agriculture and Environmental Sciences Haramaya University Dire Dawa Ethiopia

Sorghum is a staple food crop in Ethiopia and its production is mainly constrained by drought, other environmental factors, and the use of low-yielding, local sorghum varieties. To improve sorghum productivity, it is crucial to provide farmers with high yielding, stable sorghum cultivars that are tolerant to drought and other constraints. The stable performance of sorghum varieties in a growing region is critical to obtain a high and stable yield. In the 2012-2014 crop year, 24 genotypes, including standard controls, were evaluated at the national variety trial stage over six main dry lowland sorghum growing sites and two years made 7 environments to evaluate their performance, stability and to quantify Genotype by Environment Interaction (GEI) across moisture stress sorghum growing areas of Ethiopia. Spatial modeling has been used to estimate predicted mean (BLUPs) results and Performance and estimation of environmental correlation, heritability, GEI, and other parameters using the ASReml3-R analysis package. The predicted mean yield of the test genotypes across the environment ranged from 3.45 to 1.56 t·ha-1. Based on the result genotype G13, it could be further promoted because of its yield advantage and other important attributes over the standard checks, but it is the least stable. Based on the analyzed result, two mega environments were formed and Environment 1 (E1) is identified as an ideal environment among the testing environments.

关键词： Genetic Correlation Mega Environment Stability Spatial Analysis

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