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Journal of Geographical Sciences 2017年第1期27卷 79-94页

作者： Asnake MEKURIAW Andreas HEINIMANN Gete ZELEKE Hans HURNI Kaspar HURNI Natural Resources Management Department Bahir Dar University Bahir Dar Ethiopia Geospatial Data and Technology center Bahir Dar University Bahir Dar Ethiopia center for Development and Environment University of Bern Switzerland Water and Land Resource center Addis Ababa Ethiopia

An efficient and reliable automated model that can map physical Soil and Water Conservation（SWC） structures on cultivated land was developed using very high spatial resolution imagery obtained from Google Earth and Arc GIS？ERDAS IMAGINE？and SDC Morphology Toolbox for MATLAB and statistical techniques. The model was developed using the following procedures：（1） a high-pass spatial filter algorithm was applied to detect linear features,（2） morphological processing was used to remove unwanted linear features,（3） the raster format was vectorized,（4） the vectorized linear features were split per hectare（ha） and each line was then classified according to its compass directionand（5） the sum of all vector lengths per class of direction per ha was calculated. Finallythe direction class with the greatest length was selected from each ha to predict the physical SWC structures. The model was calibrated and validated on the Ethiopian Highlands. The model correctly mapped 80% of the existing structures. The developed model was then tested at different sites with different topography. The results show that the developed model is feasible for automated mapping of physical SWC structures. Thereforethe model is useful for predicting and mapping physical SWC structures areas across diverse areas.

关键词： physical SWC structure mapping automated mathematical morphology GIS and remote sensing

Watershed prioritization for conservation planning using RUSLE and morphometric methods,Northwestern Ethiopia

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Journal of Mountain Science 2023年第8期20卷 2242-2262页

作者： Agumassie Genet GELA Daniel Ayalew MENGISTU Daniel Asfaw BEKELE Department of General Forestry Debre Markos UniversityBure 18Ethiopia Department of Geography and Environmental Studies Bahir Dar UniversityBahir Dar 79Ethiopia Geo-spatial Data and Technology center(GDTC) Bahir Dar UniversityBahir Dar 79Ethiopia

Soil erosion and the subsequent sedimentation are serious environmental *** land management coupled with intense rainfall has complicated the problem in the Ethiopian ***,soil loss costs a profound amount of the national GDP and deters land *** soil loss and prioritizing areas for conservation is imperative for proper planning and resource ***,this study aimed at estimating the mean annual soil loss rate of Gilgel Abay watershed which has critical implications on Lake Tana and Abbay River(Upper Blue Nile River),using RUSLE and morphometric analysis *** including rainfall,soil,Digital Elevation Model and land use/land cover were used to generate important parameters required for the soil loss *** collected through field observation,consultation with experts and document analysis were used for validation *** results of the study reveal that the watershed experienced an average soil loss rate of 39.8 t ha^(-1)yr^(-1).Subsequently,nearly 25%(37,038 ha)of the watershed is threatened by moderate to very severe soil *** the four sub watersheds,sub watershed 3(S3)and sub watershed 4(S4),which consist of about 65%(105,000 ha)of the total area of the study watershed,experienced an annual soil loss rate of over 30 t ha^(-1)yr^(-1).The amount of soil loss that the study watershed has experienced is above the soil loss tolerance level of Ethiopia(2-18 t ha^(-1)yr^(-1))and the tropical region(10 t ha^(-1)yr^(-1)).Similarly,the results of morphometric analysis showed that the studied watershed has S-shaped hypsometric curve,an indication for maturity stage of landscape *** studied watershed is also characterized by a non-circular shaped drainage with rugged and dissected topography that contributes to high flash flood,peak discharge and incidence of soil *** result of both models signified that S3 and S4 are highly susceptible to soil ***,t

关键词： Soil loss RUSLE model Morphometric analysis Gilgel Abay watershed

Perspectives of Vertical Axis Wind Turbines in Cluster Configurations

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Fluid Dynamics & Materials Processing 2024年第12期20卷 2657-2691页

作者： Ryan Randall Chunmei Chen Mesfin Belayneh Ageze Muluken Temesgen Tigabu College of Automation Qingdao UniversityQingdao266071China center for Renewable energy Addis Ababa Institute of TechnologyAddis Ababa UniversityAddis Ababa1000Ethiopia BTeQ R&D Labs Addis Ababa1000Ethiopia bahir dar energy center Bahir Dar Institute of TechnologyBahir Dar UniversityBahir Dar6000Ethiopia

Vertical Axis Wind Turbines(VAWTs)offer several advantages over horizontal axis wind turbines(HAWTs),including quieter operation,ease of maintenance,and simplified ***,despite the prevailing belief that HAWTs outperform VAWTs as individual units,VAWTs demonstrate higher power density when arranged in *** phenomenon arises from positive wake interactions downstream of VAWTs,potentially enhancing the overall wind farm *** contrast,wake interactions negatively impact HAWT farms,reducing their *** paper extensively reviews the potential of VAWT clusters to increase energy output and reduce wind energy costs.A precise terminology is introduced to clarify ambiguous terms researchers use to quantify cluster *** examining commonly studied and proposed VAWT cluster configurations,several aspects are discussed such as aerodynamic interactions,wake characteristics,structural dynamics,and performance ***,the current state-of-the-art and research gaps are critically *** review also covers computational modeling,optimization techniques,advanced control strategies,machine learning applications,economic considerations,and the influence of terrain and application locations.

关键词： Vertical axis wind turbines(VAWTs) cluster configuration wind farm wind energy performance enhancement

Sero-prevalence and associated risk factors of Toxoplasma gondi infection among pregnant women attending antenatal care at Felege Hiwot Referral Hospital, northwest Ethiopia

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Asian Pacific Journal of Tropical Medicine 2015年第7期8卷 547-552页

作者： Kefale Awoke Endalkachew Nibret Abaineh Munshea Biology Department Bahir Dar University

Objective: To determine the prevalence of toxoplasmosis and to assess the possible risk factors associated with the infection among pregnant women attending antenatal care center at Felege Hiwot Referral Hospital, bahir dar town, northwest Ethiopia. Methods: A hospital based cross-sectional study was designed to determine the prevalence of toxoplasmosis among pregnant women. Three hundred eighty four serum samples were collected from November 2013 to January 2014. Data on socio-demographic and predisposing factors were collected from each study participant with simple random sampling technique. The serum samples were examined for anti- Toxoplasma gondii(T. gondii) antibodies using latex agglutination test. Results: The overall seroprevalence of T. gondii among the pregnant women was 18.5%. All of T. gondii positive cases found to be positive only for Ig G antibody. Significant association was observed between seroprevalence and presence of domestic cats [AOR=2.85, 95% CI: 1.66-4.90, P=0.000], consumption of raw or undercooked meat [AOR=1.98, 95% CI: 1.15-2.43, P=0.014] and history of abortion [AOR=2.47, 95% CI: 1.40-4.34, P=0.002]. No significant association was observed between seroprevalence and socio-demographic characters, gestational age, gravidity, consumption of raw vegetable, and blood transfusion. Conclusions: The seroprevalence of toxoplasmosis among pregnant women in bahir dar town was relatively high. Presence of domestic cats at home and consumption of raw or undercooked meat were identified as main risk factors for T. gondii infection. Therefore, health education towards avoiding eating raw or undercooked meat and avoiding contact with cats are recommended for prevention of miscarriage or defects during pregnancy.

关键词： Pregnant women Seroprevalence Toxoplasma gondii bahir dar Ethiopia

Effect of Polyacrylamide integrated with other soil amendments on runoff and soil loss:Case study from northwest Ethiopia

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International Soil and Water Conservation Research 2022年第3期10卷 487-496页

作者： Birhanu Kebede Atsushi Tsunekawa Nigussie Haregeweyn Mitsuru Tsubo Temesgen Mulualem Amrakh I.Mamedov Derege Tsegaye Meshesha Enyew Adgo Ayele Almaw Fenta Kindiye Ebabu Tsugiyuki Masunaga bahir dar Institute of Technology Bahir Dar UniversityP.O.Box 26Bahir DarEthiopia Arid Land Research center Tottori University1390 HamasakaTottori680-0001Japan International Platform for Dry Land Research and Education Tottori University1390 HamasakaTottori680-0001Japan College of Agriculture and Environmental Sciences Bahir Dar UniversityP.O.Box 1289Bahir DarEthiopia Faculty of Life and Environmental Science Shimane UniversityShimane Matsue690-0823Japan

Anionic polyacrylamide(PAM)has the potential to reduce soil erosion through soil ***,a comprehensive study about its effectiveness especially when applied combined with other amendments have rarely been conducted in the tropical highland climatic conditions,such as in *** study assessed the effectiveness of PAM(P=40 kg ha^(-1))alone or integrated with other soil amendments such as gypsum(G=5 t ha^(-1)),lime(L=4 t ha^(-1))and biochar(B=8 t ha^(-1))on runoff and soil loss at Aba Gerima watershed in the Upper Blue Nile basin,northwest of Ethiopia,where there is high erosion-caused soil degradation.A total of 79 daily runoff and sediment data were collected from eight runoff plots(1.3m×4m)with three replications planted with teff(Eragrostis tef)crop for two years(2018&2019)rainy *** changes in soil physicochemical properties and crop growth parameters were *** reduced seasonal runoff by 12–39%and soil loss by 13–53%.The highest reduction in runoff was observed from P+B and PAM treatments while the highest reduction in soil loss was observed from that of P+L and PAM *** PAM with other amendments improved soil structural stability,moisture content,soil pH(P+L)and organic matter(P+B),leading to favorable environment for crop growth(biomass yield)and reduced runoff and soil *** PAM,biochar and lime amendments may need more time after application to be more *** continuing the field experiment and studying physico-chemical mechanisms for extended period will better elucidate their single or combined effectiveness over time.

关键词： Dryland Soil amendments Polyacrylamide Soil erosion Soil properties

Smear positive pulmonary tuberculosis among diabetic patients at the Dessie referral hospital, Northeast Ethiopia

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Infectious Diseases of Poverty 2013年第1期2卷 39-46页

作者： Hiwot Amare Aschalew Gelaw Belay Anagaw Baye Gelaw bahir dar Regional Health Research Laboratory center Bahir DarEthiopia Department of Medical Microbiology School of Biomedical and Laboratory SciencesCollege of Medicine and Health SciencesUniversity of GondarGondarEthiopia

Background:Tuberculosis(TB)is an infectious disease which is still a major cause of morbidity and mortality throughout the *** with diabetes mellitus(DM)have a three times higher risk of developing active TB than people without ***,there is not enough credible information on the burden of pulmonary tuberculosis(PTB)among DM patients in Ethiopia,in general,and in the city of Dessie,in ***,this study aims to determine the prevalence and associated risk factors of smear positive PTB among diabetic patients at a referral hospital in ***:A cross-sectional study was conducted from February 2012 to April *** demographic characteristics were collected using a pre-tested standard questionnaire ***-morning-spot sputum specimens were collected from the study participants and examined for acid-fast bacilli using direct microscopy by the Ziehl-Neelsen staining *** was entered and analyzed using the SPSS version 16 statistical software and p-value<0.05 was considered as statistically ***:Out of 225 TB suspected diabetic patients,52%were males and 48%were *** ages ranged from 12 to 82 years,with a mean age of 47.2 *** residence(AOR:5.5;95%CI:1.07-28.20),history of TB(AOR:13.4;95%CI:2.74-65.73),contact with TB patients in the family(AOR:9.4;95%CI:1.822-48.50),and long duration of DM(AOR:8.89;95%CI:1.88-58.12)were independently associated with the development of active TB in people living with ***:The prevalence of smear positive PTB was 6.2%in TB suspected diabetic patients,which is higher compared with the general population(0.39%).Patients with a previous history of contact with TB patients,as well as those who had prolonged diabetes,were more prone to have ***,screening of diabetic patients for PTB infection during follow-up is necessary.

关键词： Dessie Diabetic patients Ethiopia Pulmonary tuberculosis(PTB)

Changes in ecosystem service values strongly influenced by human activities in contrasting agro-ecological environments

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Ecological Processes 2021年第1期10卷 691-708页

作者： Mulatu Liyew Berihun Atsushi Tsunekawa Nigussie Haregeweyn Mitsuru Tsubo Ayele Almaw Fenta Faculty of Civil and Water Resources Engineering Bahir Dar Institute of TechnologyBahir Dar UniversityP.O.Box 26Bahir DarEthiopia. Arid Land Research center Tottori University1390 HamasakaTottori 680-0001Japan. International Platform for Dryland Research and Education Tottori University1390 HamasakaTottori 680-0001Japan.

Background:Evaluating the impacts of land-use/land-cover(LULC)changes on ecosystem service values(ESVs)is essential for sustainable use and management of *** this study,we evaluated the impact of human activity driven LULC changes on ESVs over the period 1982–2016/17 in contrasting agro-ecological environments:Guder(highland),Aba Gerima(midland),and Debatie(lowland)watersheds of the Upper Blue Nile basin,***:During the study period,the continuous expansion of cultivated land at the expense of natural vegetation(bushland,forest,and grazing land)severely reduced the total ESV by about US$58 thousand(35%)in Aba Gerima and US$31 thousand(29%)in Debatie *** contrast,the unprecedented expansion of plantations,mainly through the planting of Acacia decurrens,led,from 2006,to a ESV rebound by about US$71 thousand(54%)in Guder watershed,after it had decreased by about US$61 thousand(32%)between 1982 and *** reduction in natural forest area was the major contributor to the loss of total ESV in the study watersheds,ranging from US$31 thousand(63%)in Debatie to US$96.9 thousand(70%)in Guder between 1982 and 2016/*** an areaspecific basis,LULC changes reduced the average ESV from US$560 ha^(−1) year^(−1)(1982)in Guder to US$306 ha^(−1) year^(−1)(2017)in Debatie *** ESVs such as provisioning(mainly as food production)and regulating services(mainly as erosion control and climate regulation)accounted for most of the total ESVs estimated for the study ***:In most cases,the total and specific ESVs of the watersheds were negatively associated with the population growth,which in turn was positively associated with the expansion of cultivated land over the study *** Guder,however,ESVs were positively associated with population growth,especially after *** is mainly due to the expansion of Acacia decurrens *** results suggest,therefore,that future policy measures and directions should focus o

关键词： Drought prone Agro-ecologies Land use/land cover Acacia decurrens Plantations Ecosystem services Farming practices Upper Blue Nile basin

Tillage and crop management impacts on soil loss and crop yields in northwestern Ethiopia

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International Soil and Water Conservation Research 2022年第1期10卷 75-85页

作者： Fekremariam Asargew Mihretie Atsushi Tsunekawa Nigussie Haregeweyn Enyew Adgo Mitsuru Tsubo Kindiye Ebabu Tsugiyuki Masunaga Birhanu Kebede Derege Tsegaye Meshesha Wataru Tsuji Muluken Bayable Mulatu Liyew Berihun The United Graduate School of Agricultural Sciences Tottori University4-101 Koyama-MinamiTottori680-8553Japan Amhara Regional Agricultural Research Institute P.O.Box527Bahir DarEthiopia Arid Land Research center Tottori University1390 HamasakaTottori680-0001Japan International Platform for Dryland Research and Education Tottori University1390 HamasakaTottori680-0001Japan College of Agriculture and Environmental Sciences Bahir Dar UniversityP.O.Box 1289Bahir DarEthiopia Faculty of Life and Environmental Science Shimane UniversityShimaneJapan Faculty of Civil and Water Resource Engineering Bahir Dar Institute of TechnologyBahir Dar UniversityP.O.Box252Bahir DarEthiopia Faculty of Agriculture Tottori UniversityTottoriJapan

Lack of appropriate agronomic practices is one of the major causes for soil erosion and low yields in teff(Eragrostis tef[Zucc.])production in Ethiopia.A 3-yr study was conducted at the Aba Gerima watershed in northwestern Ethiopia,to investigate the effects of two tillage practices(reduced tillage[RT]and conventional tillage[CT]),two planting methods(row planting[RP]and broadcast planting[BP]),and two compaction options(with[+T]and without[-T]trampling)on soil loss and teff yields in a split-split plot *** concentration ranged from 0.01 to 5.37 g L^(-1)(mean,0.25 g L^(-1))in our ***,the estimated total(August-October)soil loss ranged from 0.2 to 0.5 t ha^(-1)(mean,0.3 t ha^(-1)).The sediment concentration and total soil loss were significantly influenced(P<0.05)by tillage,planting methods,and trampling only in the third monitoring *** reduced soil loss by 19% relative to that of CT,whereas RP resulted in a 13%reduction in soil loss over ***-T plots showed a 15%reduction in soil loss as compared to+T *** revealed significant increase in soil total carbon and nitrogen in RT *** soil loss and greater teff grain yield were obtained in plots with improved agronomic practices(RT and RP)compared to conventional ones(CT and BP).Based on our findings we conclude that the use of RT,RP,and-T practices can effectively minimize soil loss without any crop yield penalty.

关键词： Drought-resistance Grain yield Reduced tillage Row planting Soil erosion Teff

Rural households’ livelihood vulnerability to climate variability and extremes: a livelihood zone-based approach in the Northeastern Highlands of Ethiopia

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Ecological Processes 2021年第1期10卷 749-771页

作者： Abebe Arega Mekonen Arega Bazezew Berlie Department of Geography and Environmental Studies Bahir Dar UniversityP.O.Box 79Bahir DarEthiopia Department of Geography and Environmental Studies Debremarkos UniversityP.O.Box 269DebremarkosEthiopia

Background:The adverse effects of climate variability and extremes exert increasing pressure on rural farm households whose livelihoods are dependent on ***,integrated and area-specific vulnerability assessments in Ethiopia in general and the study area,in particular,are scarce and insufficient for policy ***,this study aims to quantify,map,classify,and prioritize the level of vulnerability in terms of the components of exposure,sensitivity,and adaptive capacity in the Northeastern Highlands of *** study area is divided into six livelihood zones,namely,Abay-Beshilo Basin(ABB),South Wollo and Oromia eastern lowland sorghum and cattle(SWS),Chefa Valley(CHV),Meher-Belg,Belg,and Meher.A total of 361 sample households were selected using proportional probability sampling *** questionnaire,key informant interview,and focus group discussions were used to collect the necessary *** and temperature data were also *** the IPCC’s climate change vulnerability assessment approach,the climate vulnerability index(CVI)framework of Sullivan and Meigh’s model was used to assess the relative vulnerability of livelihoods of rural ***-four vulnerability indicators were identified for exposure,sensitivity,and adaptive capacity *** this regard,Iyengar and Sudarshan’s unequal weighting system was applied to assign a weight to ***:The results revealed that Belg and Meher were found to be the highest exposure livelihood zones to vulnerability with an aggregated value of ***,SWS,ABB,Belg,and CHV livelihood zones showed moderate level of sensitivity to vulnerability with an aggregated value between 0.45 and *** study noted that livelihood zone of Belg(0.75)was found to be at high level of livelihood ***(0.57)and CHV(0.45)were at a moderate level of livelihood vulnerability while Meher-Belg(0.22)was the least vulnerable livelihood zone due to a high level o

关键词： Exposure Sensitivity Adaptive capacity Vulnerability Index Sullivan and Meigh’s model Ethiopia

Erosion risk assessment:A contribution for conservation priority area identification in the sub-basin of Lake Tana,north-western Ethiopia

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International Soil and Water Conservation Research 2022年第1期10卷 46-61页

作者： Daniel Asfaw Bekele Getachew Workineh Gella Mulualem Asfaw Ejigu Department of Geography and Environmental Studies Bahir Dar UniversityEthiopia Geospatial Data and Technology center(GDTC) Bair Dar UniversityEthiopia Department of Geography and Environmental Studies Debre Tabor UniversityEthiopia

Soil erosion is a serious environmental problem arising from agricultural intensification and landscape *** land management coupled with intense rainfall has intricated the problem in most parts of the Ethiopian *** loss costs a profound amount of the national ***,quantifying soil loss and prioritizing areas for conservation is imperative for proper planning and resource ***,this study has modeled the mean soil loss and annual sediment yield of the Gumara *** 5 TM,Landsat 7ETM+,and Landsat 8 OLI were used for land use land cover(LULC)change *** these,other datasets related to rainfall,digital soil map,Digital Elevation Model,reference land use,and cover(LULC)ground truth points were used to generate parameters for modeling soil *** watershed was classified into five major land-use classes(water body,cultivated land,grazing land,built-up and forest and plantation)using a maximum likelihood algorithm covering a period of the last 30 years(1988-2019).The mean annual soil loss and sediment yield were quantified using RUSLE,Sediment delivery ratio(SDR),and Sediment Yields models(SY).The analysis result unveils that within the past 30 years,the watershed has undergone significant LULC changes from forest&plantation(46.33%)and grazing land to cultivated land(31.59%)with the rate of-1.42km^(2)yr^(-1) and-2.80km^(2)yr^(-1) *** the same vein,the built-up area has expanded to cultivated and grazing ***,nearly 15%(207 km2)of the watershed suffered from moderate to very severe soil *** average,the watershed losses 24.2t ha^(-1) yr^(-1) of soil and yields 2807.02t ha^(-1) yr^(-1) ***,the watershed losses 385,157t ha^(-1)yr^(-1) soil from the whole study *** the admir-ative districts,Farta(Askuma,Giribi,Mahidere Mariam and Arigo kebeles),Fogera(Gazen Aridafofota and Gura Amba kebeles),East Este(Witimera kebele),and Dera(Gedame Eyesus and Deriana Wechi

关键词： Phrases Erosion Sediment yield Landscape GIS Cumara watershed