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Impact of Land Cover Change on Water Quality and Stream Flow in Lake Hawassa Watershed of Ethiopia

Agricultural Sciences 2014年第8期5卷 647-659页

作者： Wolka Kebede mengistu tefera Taddese Habitamu Tolera Alemayehu Wondo Genet College of Forestry and Natural Resources Hawassa University Hawassa Ethiopia

Quantifying the hydrologic response of land use/land cover change (LULCC) is of paramount importance to improve land management. This study was carried out to analyze the effect of LULCC on water quality and quantity. LULCC of the watershed in 1986, 1999 and 2011 was analyzed from Landsat satellite images using supervised classification. Time series and point data were collected from the upper and lower sections of Wedesa, Wesha and Hallo Rivers. Water quality parameters (turbidity, suspended solid (SS), total dissolved solid (TDS), pH, electric conductivity (EC), total organic carbon (TOC), ammonia, nitrate and phosphate) were analyzed in the laboratory. A considerable decline in forest and an increase in woodland were observed in the watershed during the indicated periods. Turbidity, SS, TDS and EC were significantly higher (P < 0.05) in the lower section of the rivers compared to the upper ones. Ammonia, nitrate and phosphate were higher in the lower section of some rivers compared to the upper ones. In general, water quality in the upper watershed of the three rivers was better than the lower one with respect to considered parameters, which might be related to the observed LULCC. Most water quality parameters varied (P < 0.05) seasonally in both the upper and lower sections of the rivers. Despite the irregular rainfall pattern and increased water consumption from the catchment, the annual discharge of the Tikur-Wuha River to Lake Hawassa shows an increasing trend. We concluded that the discharge is not only related to the upstream LULCC but also to the management of the Cheleleka wetland. However, further investigation is required to determine the dominant factors affecting inflow discharge to Lake Hawassa.

关键词： Discharge Ethiopia Lake Hawassa Water Quality Wetland

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Modeling the System for Hybrid Renewable Energy Using Highly Efficient Converters and Generator

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CES Transactions on Electrical Machines and Systems 2024年第3期8卷 356-366页

作者： tefera Kitaba Department of Electrical Power Engineering Ethiopian Defence University College of EngineeringBishoftuDebre Zeit 1041Ethiopia

High-efficient isolated DC/DC converters with a high-efficiency synchronous reluctance generator(SRG)are the ultimate solutions in DC microgrid *** design and modeling of isolated DC/DC converters with the performance of SRG are carried *** the generator side,reactive and active powers are used as pulse width modulation(PWM)control ***,the flux estimator is ***-phase PWM rectifier is used by applying space vector modulation(SVM)with a constant switching frequency for direct power ***,the paper also includes the experimental validation of the *** paper also proposes that highly efficient power converters and synchronous reluctance generators are required to achieve high performance for hybrid renewable energy systems applications.

关键词： DC-DC Duty ratio Isolated DTC SRG Converters

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Cauchy matrix approach to three non-isospectral nonlinear Schrödinger equations

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Communications in Theoretical Physics 2024年第5期76卷 1-15页

作者： Alemu Yilma tefera Shangshuai Li Da-jun Zhang Department of Mathematics Shanghai UniversityShanghai 200444China Newtouch Center for Mathematics of Shanghai University Shanghai 200444China Department of Applied Mathematics Faculty of Science and EngineeringWaseda UniversityTokyo 169-8555Japan

This paper aims to develop a direct approach,namely,the Cauchy matrix approach,to non-isospectral integrable *** the Cauchy matrix approach,the Sylvester equation plays a central role,which defines a dressed Cauchy matrix to provideτfunctions for the investigated *** this paper,using the Cauchy matrix approach,we derive three non-isospectral nonlinear Schrödinger equations and their explicit *** equations are generically related to the time-dependent spectral parameter in the Zakharov–Shabat–Ablowitz–Kaup–Newell–Segur spectral *** solutions are obtained from the solutions of unreduced non-isospectral nonlinear Schrödinger equations through complex *** solutions are analyzed and illustrated to show the non-isospectral effects in dynamics of solitons.

关键词： Cauchy matrix approach Sylvester equation nonlinear Schrödinger equation non-isospectral integrable system explicit solution

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Cauchy matrix approach to three non-isospectral nonlinear Schr?dinger equations

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Communications in Theoretical Physics 2024年第5期 3-17页

作者： Alemu Yilma tefera Shangshuai Li Da-jun Zhang Department of Mathematics Shanghai University Newtouch Center for Mathematics of Shanghai University Department of Applied Mathematics Faculty of Science and Engineering Waseda University

This paper aims to develop a direct approach, namely, the Cauchy matrix approach, to non-isospectral integrable systems. In the Cauchy matrix approach, the Sylvester equation plays a central role, which defines a dressed Cauchy matrix to provide τ functions for the investigated equations. In this paper, using the Cauchy matrix approach, we derive three non-isospectral nonlinear Schr?dinger equations and their explicit solutions. These equations are generically related to the time-dependent spectral parameter in the Zakharov–Shabat–Ablowitz–Kaup–Newell–Segur spectral problem. Their solutions are obtained from the solutions of unreduced non-isospectral nonlinear Schr?dinger equations through complex reduction. These solutions are analyzed and illustrated to show the non-isospectral effects in dynamics of solitons.

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Solar Cooling Alternatives for Residential Houses

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Journal of Civil Engineering and Architecture 2024年第7期18卷 348-362页

作者： Meron Mulatu mengistu Bahir Dar Institute of Technology Bahir Dar UniversityBahir Dar 26Ethiopia

The energy consumption rate of non-OECD(non-Organisation for Economic Co-operation and Development)countries rises about 2.3 percent per year as compared to the OECD countries which is 0.6 *** developing countries use energy efficient technology and integrate renewable energy systems in the new building their carbon dioxide emission rate reduces by 25 to 44 ***,even now,renewable energy integrated buildings are hardly considered while constructing *** paper focuses on the study of solar cooling system options for residential house of Bahir Dar city,in *** meet the demand of housing in the city,different types of apartments and villa houses are under *** the analysis case study was made focusing on two types of residential houses,condominium apartment and Impact Real Estate Villa *** results of IDA ICE software show that the average operative temperatures and cooling loads for condominium apartment and Real-estate Vila are 31.8℃ and 30.7℃,5.53 kW and 5.73 kW *** of the residences are not satisfied at this operating *** are different types of solar cooling *** sorption cooling systems are commonly used which can also be classified into absorption,adsorption and desiccant cooling *** adsorption cooling systems are easy to manufacture locally as compared to solar absorption cooling *** do not have moving *** of the working medium pairs used in adsorption cooling system are:activated carbon/ammonia,silica gel/water,zeolite/*** chillier with silica gel/water as a working pair was selected since it can operate at regeneration/desorption temperature as low as 45℃ coming from flat plate *** 75℃ regeneration temperature,the system delivers 9℃ chilled water *** cooling load simulation result direct solar irradiation is the highest source of cooling load for both *** gives an opportunity for passive solar cooling

关键词： Adsorption cooling load condominium impact real-estate IDA ICE

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Community Caregivers’ Experiences and Programmatic Strategies to Improve Active Case Finding in Community Tuberculosis Care in Botswana 2016-2021

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Journal of Tuberculosis Research 2024年第2期12卷 105-118页

作者： Unami Modongo-Mathebula Mary Moleki tefera Agizew Faculty of Health Sciences University of South Africa Pretoria South Africa Department of Family Medicine and Public Health Faculty of Medicine University of Botswana Gaborone Botswana

Background: The community tuberculosis care program was started to reduce the impact of TB and increase successful treatment outcomes, thus contributing to meeting WHO targets on TB. According to the Botswana Ministry of Health, community tuberculosis care was introduced with the main goal of reducing tuberculosis-related morbidity and mortality among communities through the expansion of direct observed therapy and community involvement to community settings. The community caregivers were to support tuberculosis patients throughout their treatment period until they were cured or had completed their treatment. Settings: Two major cities of Botswana, Francistown and Gaborone, with more than twenty-two health clinics offering tuberculosis care. Objective: To investigate community caregivers’ experiences and identify programmatic strategies to improve active TB case findings under the community TB care (CTBC) program in Botswana during 2016-2021. Methods: We adopted a descriptive qualitative research design, followed by convenience purposive sampling. We obtained consent and interviewed 40 participants who met the inclusion criteria, 16 out of 73 in Gaborone and 24 out of 38 from Francistown. Results: We interviewed 40 caregivers with a mean age of 43.4 years. Accepting the caregiving role was identified as the main experience by more than two thirds of the caregivers. While at least more than two-fifth felt obligated to care for the patient at home due to personal relations. More than half of the respondents found caregiving difficult or frustrating due to some challenges encountered during the caregiving role. Behavioral modifications were suggested under different subthemes as strategies to improve active case finding. [-rId13-]Conclusion: Acceptance was the major experience in CTBC. Intensification of known programmatic strategies was suggested by caregivers to improve tuberculosis active case finding in CTBC.

关键词： Community Experiences Caregivers Active Case Finding Tuberculosis Community Tuberculosis Care

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Farmers' decision to adopt watershed management practices in Gibe basin, southwest Ethiopia

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International Soil and Water Conservation Research 2019年第4期7卷 376-387页

作者： Fekadu mengistu Engdawork Assefa Center for Environment and Development Studies Addis Ababa UniversityAddis AbabaEthiopia Department of Geography and Environmental Studies Debre Berhan UniversityDebre BerhanEthiopia

Watershed management practices have been implemented to avert land degradation and to enhance people's livelihoods in the highlands of Ethiopia for several ***,the successes of these practices have been quite limited and the main factors affecting these practices have not been examined in *** study intended to investigate rates and intensities of adoption of watershed management practices and to determine the main factors affecting farmers' adoption decisions in the upper Gibe *** were collected from 304 household heads in six sub catchments across different topographic settings using household *** groups discussions,key informant interviews and transect walk observations were also *** statistics and econometric models such as,multivariate and ordered probit were used to analyze the *** results revealed that the majority of households (82.6 percent) used at least one of the six practices considered in this *** bund,grass strip cultivation with soil bund and compost were the major watershed management practices adopted by *** rate and intensity of adoption were better for program participants and in upper and middle topographic *** results of the multivariate and ordered probit analysis indicated that household size,extension services,credit services,training services and perception of soil erosion had positive significant relationship with both rate and intensity of adoption of most ***,policy makers and planners need to consider labor,knowledge and awareness,and capital intensive nature of the practices for the up scaling planning and implementations of watershed intervention technologies.

关键词： Watershed management practices Farmers' decision Adoption Determinants Gibe river basin

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Structure and regeneration status of woody species in the Munessa Forest,Southern Ethiopia

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Journal of Forestry Research 2021年第2期32卷 493-501页

作者： mengistu Gelasso Junqing Li Department of Forest Ecology College of ForestryBeijing Forestry UniversityP.O.Box 100083BeijingPeople’s Republic of China

This study evaluates the structure and regeneration status of woody species in the Munessa Forest,a dry Afromontane forest in southern *** data were collected using a systematic sampling *** and distribution of seedlings,saplings and mature trees were assessed along an altitudinal gradient using quadrats of different *** number of individuals,frequencies,heights and DBH of species>1 m and DBH>2.5 cm were recorded in altitudinal bands of 100 *** of the vegetation structure shows that the density of woody species decreases as DBH and height class *** area of stems with DBH>2.5 cm was 53.4 m^(2)ha^(−1).Population structure and regeneration patterns indicate a significant degradation of the forest due to anthropogenic *** was better for less valuable woody species than for species with economic and ecological *** suggests a discontinuous recruitment of these species due to selective cutting of middle and higher diameter ***,enrichment planting of high value,endangered species is necessary to maintain them as part of this *** is a need to develop and implement an effective forest management plan for sustainable use of these forest resources.

关键词： Woody species Altitudinal gradient Regeneration status Structural distribution

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Pleiotropy Structures Plant Height and Seed Weight Scaling in Barley despite Long History of Domestication and Breeding Selection

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Plant Phenomics 2023年第1期5卷 85-93页

作者： Tianhua He tefera Tolera Angessa Chengdao Li Western Crop Genetics Alliance Agricultural SciencesCollege of ScienceHealthEngineering and EducationMurdoch UniversityMurdochWAAustralia Agriculture and Food Department of Primary Industries and Regional DevelopmentSouth PerthWAAustralia

Size scaling describes the relative growth rates of different body parts of an organism following a positive *** and crop breeding often target the scaling traits in the opposite *** genetic mechanism of the size scaling influencing the pattern of size scaling remains ***,we revisited a diverse barley(Hordeum vulgare L.)panel with genome-wide single-nucleotide polymorphisms(SNPs)profile and the measurement of their plant height and seed weight to explore the possible genetic mechanisms that may lead to a correlation of the two traits and the influence of domestication and breeding selection on the size *** height and seed weight are heritable and remain positively correlated in domesticated barley regardless of growth type and *** structural equation modeling systematically evaluated the pleiotropic effect of individual SNP on the plant height and seed weight within a trait correlation *** discovered seventeen novel SNPs(quantitative trait locus)conferring pleiotropic effect on plant height and seed weight,involving genes with function in diverse traits related to plant growth and *** disequilibrium decay analysis revealed that a considerable proportion of genetic markers associated with either plant height or seed weight are closely linked in the *** conclude that pleiotropy and genetic linkage likely form the genetic bases of plant height and seed weight scaling in *** findings contribute to understanding the heritability and genetic basis of size scaling and open a new venue for seeking the underlying mechanism of allometric scaling in plants.

关键词： breeding scaling Plant

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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

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