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Open Journal of Ecology 2017年第13期7卷 667-681页

作者： bedilu bekele mengistu Dikaso Unbushe Eyualem Abebe College of Natural Science Arba Minch University Ethiopia Department of Natural Sciences Pharmacy and Health Professions Elizabeth City State University Elizabeth City NC USA

Macrophytes play critical ecological role in inland water bodies, especially in shallow systems. Water hyacinth (Eichhornia crassipes) is an invasive plant species introduced to Ethiopian water bodies around the mid 20th century with recently exacerbated devastating ecological and economic consequences. Here we report the impact of the invasive plant species on macrophyte species assemblage and biodiversity in Lake Abaya, southwestern Ethiopia. We compared four sites in Lake Abaya, two hyacinth infested and two non-infested, each site consisting of 15 plots. Our results showed that water hyacinth affects the macrophyte community composition, abundance and diversity negatively. Even though some macrophyte species from the Poaceae and Cyperaceae families appear to coexist with the alien plant, the invasive species has reduced macrophyte abundance and diversity at the infested sites, and in some cases changed the community to nearly monotypic flora. Our data affirm that water hyacinth has the potential to alter macrophyte composition, abundance and diversity in the wider Ethiopian aquatic ecosystems. A broad & closer, systematic and comprehensive look at the short and long term consequences of its expanding invasion within the framework of specific local environmental, ecological and societal conditions is long-overdue.

关键词： Macrophytes Eicchornia crassipus Composition Abundance Wetland

Provenance and Paleoclimate of the Triassic to Middle Jurassic Adigrat Sandstone,Blue Nile Basin,Central Ethiopia

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 1007-1020页

作者： bekele BARSISA Ayalew DEREJE Kidanemariam GILAMICHAEL Atnafu BALEMWAL Raphaël PIK Department of Earth Sciences Wollega UniversityNekemteEthiopia Department of Earth Sciences Addis Ababa UniversityAddis AbabaEthiopia Departments of Anthropology Geography and GeologyEast Los Angeles CollegeLos AngelesCaliforniaUSA CRPG(UMR 7358 CNRS&Universitéde Lorraine) 15 rue ND des pauvres BP2054501 Vandoeuvre-Lès-Nancy CedexFrance

Mineralogical and geochemical studies have been undertaken on the Triassic to Lower Jurassic Adigrat Sandstone of the Blue Nile Basin of central Ethiopia to infer its source rock type,paleoweathering,and paleoclimatic *** Adigrat Sandstone occurs at the basal section of the Mesozoic sedimentary formation and unconformably overlays the Neoproterozoic–Paleozoic crystalline rocks,or locally,the Karroo sediments in the northern Blue Nile Basin.A mineralogical study reveals that quartz(Q),feldspars(F),and lithic fragments(L)are the framework grains of the *** the QFL diagram,the plot of the modal composition of the sandstone mainly falls within the feldspathic arenite and quartzose arenite *** geochemical data of the lower section of the sandstone mainly falls within the arkose and subarkose fields,whereas the upper section data falls within the quartzose and sublithic arenite *** and geochemical weathering indices indicate that the provenances of the Adigrat Sandstone were exposed to pronounced weathering intensity,where the lower part of the sandstone was controlled by arid to semi-arid conditions,whereas the upper section was linked to humid to semi-humid(tropical to subtropical)climatic *** and geochemical data also indicate that mafic to intermediate basement rocks were the primary source rocks of the *** the sediment was assumed to have been reworked by multi-cyclic sedimentary *** discriminant function diagram,the REE pattern,La/Th ***/Yb,and the Th–Hf–Co plot are consistent.A comparison of provenance studies for the Adigrat Sandstone in the Blue Nile Basin and the Mekele outlier of northern Ethiopia indicates that the sediment of the former is highly sorted,experienced higher weathering intensity,and compositionally derived from mafic to intermediate crystalline *** the other hand,the sediment of the latter is essentially a weathering product of felsic rocks.

关键词： mineralogical geochemical paleoweathering humid provenance Adigrat Sandstone

Energy potential assessment and techno-economic analysis of micro hydro-photovoltaic hybrid system in Goda Warke village,Ethiopia

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Clean Energy 2024年第1期8卷 237-260页

作者： Ephrem Assefa Feyissa Getachew Shunki Tibba Tarekegn Limore Binchebo Endeshaw Alemu bekele Adem Tibesso Kole Department of Mechanical Engineering Bule Hora UniversityBule HoraEthiopia Agro Technical and Technology College Menschen fuer Menschen FoundationHararEthiopia Faculty of Mechanical Engineering Jimma Institute of TechnologyJimmaEthiopia Department of Thermal Technology Silesian University of TechnologyGliwicePoland Jimma Agricultural Engineering Research Center JimmaOromia Agricultural Research InstituteEthiopia

Rural Ethiopia has significant untapped potential for hydro and solar energy generation ***,challenges arise from seasonal variations and unfavourable topographic positions of flowing rivers,hindering the efficient exploitation of these *** the country’s abundance in hydro and solar energy resources,>75%of the population still lack access to electricity from the national *** work deals with energy resource potential assessment and techno-economic analysis of micro hydro-photovol-taic(PV)hybrid systems,considered in the case study of Goda Warke village,located in the Yaya Gulele district.A novel framework is proposed that utilizes the Natural Resource Soil Conservation Service curve number method to assess the energy potential of micro-hydro energy in ungauged basins,specifically at the exit point of the Girar River basin *** average monthly flow rate in the basin is 0.975 m3/s,while the area exhibits a solar radiation potential of 5.39 kWh/m^(2)/*** policy promotes expanding ac-cess to modern energy sources and utilization of indigenous energy *** results indicate that the hydro/PV/diesel generator(DG)/battery and hydro/PV/battery systems are the most optimal choices based on net present cost,with the inclusion of a DG for economic ***-hydro energy covers most of the electric load in the area,achieving a capacity factor of 47.5%.The cost of energy and net present cost were found to be sensitive to variables such as the price of diesel fuel,pipe head loss,and the growth of the village *** optimized system demonstrated a hydro energy potential of 1405.37 MWh/year and a PV energy output of 274.04 MWh/year,resulting in a levelized cost of energy of 0.0057 and 0.049$/kWh for the hydro and PV components,respectively.

关键词： energy potential hybrid micro hydro-photovoltaic Natural Resource Soil Conservation Service curve number sensitivity variable

Association of Serum Folate and Vitamin B_(12) Concentrations with Obesity in Chinese Children and Adolescents

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Biomedical and Environmental Sciences 2024年第3期37卷 242-253页

作者： ZHU Qian Rang KOK E Dieuwertje bekele Hailu Tesfaye MANUSAMA Koen ZHANG Jing Xian XIE Wei ZONG Wen Qi ZUO Hui ZHANG Jian KAMPMAN Ellen DAI Yue Jiangsu Provincial Center for Disease Control and Prevention Nanjing 210009JiangsuChina Division of Human Nutrition and Health Wageningen University&ResearchWageningen 176700 AAThe Netherlands School of Public Health Medical College of Soochow UniversitySuzhou 215123JiangsuChina National Institute for Nutrition and Health Chinese Center for Disease Control and PreventionBeijing 100050China

Objective This study aimed to evaluate the associations of serum folate and/or vitamin B12 concentrations with obesity among Chinese children and *** A cross-sectional study was conducted including 3,079 Chinese children and adolescents,aged 6 to 17 years,from Jiangsu,*** indices,such as,children's body mass index(BMI),BMI z-scores,waist circumference,and waist-to-height ratio were *** linear regression and generalized additive models were used to investigate the associations of serum folate and vitamin B12 levels with anthropometric indices and odds of *** We observed that serum vitamin B12 concentrations were inversely associated with all anthropometric indices and the odds of general obesity[odds ratio(OR)=0.68;95%confidence interval(CI)=0.59,0.78]and abdominal obesity(OR=0.68;95%CI=0.60,0.77).When compared to participants with both serum vitamin levels in the two middle quartiles,those with both serum folate and vitamin B12 levels in the highest quartile were less prone to general(OR=0.31,95%CI=0.19,0.50)or abdominal obesity(OR=0.46,95%CI=0.31,0.67).Conversely,participants with vitamin B12 levels in the lowest quartile alongside folate levels in the highest quartile had higher odds of abdominal obesity(OR=2.06,95%CI=1.09,3.91).Conclusion Higher serum vitamin B12 concentrations,but not serum folate concentrations,were associated with lower odds of childhood *** and adolescents with high levels of vitamin B12 and folate were less likely to be obese.

关键词： Folate Vitamin B12 Childhood obesity Micronutrient

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

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山地科学学报(英文) 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

Physics-informed deep learning for one-dimensional consolidation

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第2期13卷 420-430页

作者： Yared W.bekele Rock and Soil Mechanics Group SINTEF ASTrondheimNorway

Neural networks with physical governing equations as constraints have recently created a new trend in machine learning *** this context,a review of related research is first presented and *** potential offered by such physics-informed deep learning models for computations in geomechanics is demonstrated by application to one-dimensional(1D)*** governing equation for 1D problems is applied as a constraint in the deep learning *** deep learning model relies on automatic differentiation for applying the governing equation as a constraint,based on the mathematical approximations established by the neural *** total loss is measured as a combination of the training loss(based on analytical and model predicted solutions)and the constraint loss(a requirement to satisfy the governing equation).Two classes of problems are considered:forward and inverse *** forward problems demonstrate the performance of a physically constrained neural network model in predicting solutions for 1D consolidation *** problems show prediction of the coefficient of ***’s problem,with varying boundary conditions,is used as a numerical example and the deep learning model shows a remarkable performance in both the forward and inverse *** the application demonstrated here is a simple 1D consolidation problem,such a deep learning model integrated with a physical law has significant implications for use in,such as,faster realtime numerical prediction for digital twins,numerical model reproducibility and constitutive model parameter optimization.

关键词： Physics-informed deep learning Consolidation Forward problems Inverse problems

Fluid inclusion studies of the Kenticha rare-element granite-pegmatite,Southern Ethiopia

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Acta Geochimica 2022年第6期41卷 926-946页

作者： Barsisa bekele Amit Kumar Sen Department of Earth Sciences Indian Institute of Technology RoorkeeRoorkeeIndia Department of Earth Sciences Wollega UniversityNekemteEthiopia

In the Kenticha area,a series of barren to rare metal-bearing pegmatites intruded into the Neoproterozoic Adola *** pegmatites host world-class Nb and Ta deposits and significant Li and Be *** this contribution,fluid inclusion data and feldspar geothermometry have been combined to define the crystallization condition of the Kenticha rare-metal *** and complex assemblages of secondary fluid inclusions representing episodic fluid circulations have been identified in quartz and spodumene.A primary aqueous-carbonic fluid of low salinity aqueous solution with liquid and vapour CO_(2) phases,secondary carbonic fluid rich and carboniconly fluids,and multiple generations of secondary aqueous inclusions that represent sub-solidus hydrothermal circulation have been *** aqueous inclusions were homogenized into the liquid phase between 100 and 290℃.Aqueous-carbonic inclusions were homogenized,usually via a critical transition[T_(h)(LV→SCF)]between 241 and 397℃,or less commonly,via a dew-point transition[T_(h)(LV→V)]between 213 and 264℃.Crystallization of the rare-element pegmatite is certainly associated with the late-stage magmatic or early hydrothermal low-salinity aqueous-carbonic fluid that homogenizes to critical conditions.A combination of microthermometric data and existing experimentally determined solidus from flux and volatile bearing haplogranite suggests exsolution of fluids from hydrous silicate melt,perhaps during crystallization of the aplitic *** fluids were then trapped and isobarically cooled along a reasonable geothermal gradient within the pegmatite unit down to a temperature of around 397℃.

关键词： Fluid inclusions Microthermometry Pegmatite Cooling-path Boiling Kenticha

Demography and dynamics of mountain nyala Tragelaphus buxtoni in the Bale Mountains National Park,Ethiopia

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Current Zoology 2010年第6期56卷 660-669页

作者： Yosef MAMO Michelle A.PINARD Afework bekele Hawassa University Department of Wildlife and Eco-tourism University of Aberdeen Institute of Biological and Environmental Sciences Addis Ababa University Department of Biology

We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on demographics and movement patterns. The population＇s age-group composition was 58% adults, 25% sub-adults, 9% juveniles, 5% calves and 3% unidentified with a female-male sex ratio of 2：1. Population density was found to be significantly different between the two sub-populations （Dinsho Sanctuary and Gaysay/Adelay）. A significant difference was found for age-group composition across the two sub-populations except adult females, sub-adult males and calves. The Dinsho sub-population was an isolated group. Separation and containment of the mountain nyala population could have negatively affected their ability to search for habitat requirements and mates from distant areas. The population varied between 830-908 individuals （95% CI）, a reduction of 45% from earlier reports. However, the mean population density increased due to contraction of the species＇ habitat range. We observed a population decrease of 2%-5% per year over the course of our study. Many of the assessed demographic parameters did not significantly change over the three years. This suggests that the decrease in nyala population was not due to random variations in reproduction. Anthropogenic factors such as competition with livestock for forage, habitat encroachment and poaching by the local people might have been partly responsible for the depleted population in our study areas [Current Zoology 56 （6）： 660q569, 2010].

关键词： Density Dynamics Group size Mountain nyala Movement Sex ratio

Soil and water conservation practice effects on soil physicochemical properties and crop yield in Ethiopia:review and synthesis

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Ecological Processes 2022年第1期11卷 206-221页

作者： Endale bekele Jiru Habtamu Temesgen Wegari College of Agriculture and Natural Resource Dilla UniversityDillaEthiopia College of Agriculture and Natural Resource Bonga UniversityBongaEthiopia

Background:Land degradation is an urgent agenda that requires great effort and resources to *** worsens soil components through disrupting ecological functions and threatens agriculture *** overcome it,different soil and water conservation(SWC)practices have been undertaken in numerous parts of *** paper aims to review the effects of SWC practices on soil physicochemical properties and crop *** were collected from secondary sources via a computer library using various databases based on developed *** collected data were organized,categorized,and analyzed through descriptive *** mean difference of selected soil physicochemical properties obtained from treated and untreated farmland was tested using paired *** influencing crop yield on treated farmland were determined by a multiple linear regression ***:SWC practices influenced the soil physicochemical properties and crop yield either positively or *** mean values of available phosphorus(10.6 ppm,8.7 ppm),total nitrogen(0.5%,0.4%),soil pH(6.0%,5.8%),soil organic matter(4.4%,3.8%),and soil organic carbon(2.2%,1.8%)were on treated and untreated farmland under physical SWC practices,***,the mean values of these variables were higher on treated farmland than untreated farmland under both biological and integrated SWC *** mean value of bulk density was higher on untreated farmland than treated one and statistically significant under all SWC *** juu and stone-faced soil bund constantly increased crop yield,whereas soil bund and stone bund did ***:Proper implementation of SWC technologies through integrating physical and biological measures will boost the effectiveness of the practice in restoring soil physicochemical properties and improving crop ***,government due attention paid for land resources management in Ethiopia,whereby the annual SWC and tree planting campaign und

关键词： Land degradation Soil and water conservation Crop yield Soil physicochemical properties

Anthropogenic effects on floristic composition, diversity and regeneration potential of the Debrelibanos Monastery forest patch, central Ethiopia

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Journal of Forestry Research 2019年第6期30卷 2151-2161页

作者： Wakshum Shiferaw Tamrat bekele Sebsebe Demissew College of Natural Sciences Plant Biology and Biodiversity Management Addis Ababa University

This study assesses the effects of human disturbance on:(1)floristic composition,diversity,and plant community types;and,(2)the regeneration potential of woody species in the Debrelibanos Monastery forest patch in the North Showa zone of Oromia National Regional State,*** sample quadrats were placed on parallel transect lines along altitudes in the forest using a systematic sampling *** of 1 m^2,100 m^2 and 400 m^2 were used for recording herbaceous/seedling,sapling and tree species,respectively,with symptoms of different human disturbance *** hundred and thirteen species belonging to 52 families were recorded in the forest *** results show 459.5 stems ha^-1 of tree/shrub species *** community types,namely Juniperus procera–Acacia lahai,Carissa spinarum–Acacia abyssinica,Olea europaea ***–Euphorbia abyssinica and Ficus sur–Allophylus abyssinicus were *** overall Shannon–Wiener diversity index was *** regeneration patterns of some species were ***,altitude and human activities had significant effects on vegetation patterns and imply that current management practices are not satisfactory to sustain the *** improved management interventions are made,the sustainability of forest services will be at stake.

关键词： Anthropogenic impacts Composition Community Debrelibanos Diversity