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Investigation of Laser Induced Breakdown Spectroscopy(LIBS)for the Differentiation of Nerve and Gland Tissue-A Possible Application for a Laser Surgery feedback Control Mechanism

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Plasma Science and Technology 2016年第6期18卷 654-660页

作者： f.mehari M.ROHDE C.KNIPfER R.KANAWADE f.KLAMPfL W.ADLER N.OETTER f.STELZLE M.SCHMIDT Clinical Photonics Lab Erlangen Graduate School in Advanced Optical Technologies(SAOT)Friedrich-Alexander-Universitat Erlangen-NurnbergPaul-Gordan-Str.691052 ErlangenGermany Institute of Photonic Technologies Friedrich-Alexander-Universitat Erlangen-NiirnbergKonrad-Zuse-Str.3/591052 ErlangenGermany Department of Oral and Maxillofacial Surgery University Hospital ErlangenFriedrich-Alexander-Universitat Erlangen-NurnbergGliickstrasse 1191054 ErlangenGermany Chair of Biometry and Epidemiology Friedrich-Alexander-Universitat Erlangen-Niirnberg Waldstrabe 691054 ErlangenGermany

Laser surgery provides clean,fast and accurate modeling of ***,the inability to determine what kind of tissue is being ablated at the bottom of the cut may lead to the iatrogenic damage of structures that were meant to be *** this context,nerve preservation is one of the key challenges in any surgical *** example is the treatment of parotid gland pathologies,where the facial nerve（***） and its main branches run through and fan out inside the glands parenchyma.A feedback system that automatically stops the ablation to prevent nerve-tissue damage could greatly increase the applicability and safety of surgical laser *** the present study,Laser Induced Breakdown Spectroscopy（LIBS） is used to differentiate between nerve and gland tissue of an ex-vivo pig animal *** LIBS results obtained in this preliminary experiment suggest that the measured spectra,containing atomic and molecular emissions,can be used to differentiate between the two tissue *** measurements and differentiation were performed in open air and under normal stray light conditions.

关键词： laser induced breakdown spectroscopy plasma chemical composition nerveparotid gland

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The invasion of Prosopis juliflora and Afar pastoral livelihoods in the Middle Awash area of Ethiopia

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Ecological Processes 2015年第1期4卷 145-153页

作者： Zeraye H.mehari Natural Resources Research Division Werer Agricultural Research CenterEthiopian Institute of Agricultural Research(EIAR)Addis Ababa 2003Ethiopia

Introduction:An evergreen shrub,Prosopis juliflora is one of the most invasive species in arid and semi-arid *** its introduction to the Middle Awash area of Ethiopia,it has invaded a huge acreage of grass-and rangelands which are life-supporting unit for Afar ***:Survey,using group discussion and questionnaire,was made to study the effect of *** invasion on Afar pastoral *** obtained data were analyzed using Wilcoxon signed-rank test,chi-square analysis,and logistic ***:According to the result,84%of the total surveyed households rated *** as undesirable species even though the bush was often used for fuelwood,fencing homesteads,and barn and house *** of *** was also blamed to limit transhumance,occupying settlement areas and affecting multipurpose trees/bushes and grass *** these effects put pressure on the livestock assets causing about 80%livestock loss,testing the pastoral livelihoods *** household,on average,lost 6.5 small stock and 7 cattle during the past 10 years due to health hazards caused by *** ***,*** as a source of income was considered by a quarter of the surveyed pastoral households,with the age of a household head and change in livestock asset being influential variables in ***:In sum,*** invasion has made livestock rearing extremely difficult which raised pastoralists’ecological vulnerability in the fragile ecosystem they possess.

关键词： Afar pastoralists Middle Awash area Prosopis juliflora Invasion Livestock Livelihoods

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Ecological and floristic study of Hirmi woodland vegetation in Tigray Region,Northern Ethiopia

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Ecological Processes 2020年第1期9卷 615-633页

作者： mehari Girmay Tamrat Bekele Sebsebe Demissew Ermias Lulekal Ministry of Mining and Petroleum of Ethiopia P.O.Box 486Addis AbabaEthiopia Department of Plant Biology and Biodiversity Management Addis Ababa UniversityP.O.Box 3434Addis AbabaEthiopia

The dryland area in Ethiopia covers a substantial region endowed with diverse plant ***,the landmass has received less attention even if it has high ecological,environmental,and economic *** present study was conducted in Hirmi woodland vegetation,which is one of the dryland areas in Ethiopia,with the objective of investigating the floristic composition,plant community types,vegetation structure,communityenvironment relations and its regeneration *** and environmental data were collected from 80 sampling plots with a size of 25 m×25 m designated as the main *** at breast height(DBH),height,basal area,density,vertical structure,importance value index(IVI),and frequency were *** diversity and evenness were analyzed using Shannon diversity and evenness *** plant community types and vegetation-environment relationships were analyzed using classification and ordination tools,respectively.A total of 171 vascular plant species belonging to 135 genera and 56 families were *** 5.3%of the species were endemic and near-endemic to *** highest number of species was recorded in families fabaceae(16.4%)and Poaceae(11.7%)followed by Asteraceae(7.0%),Combretaceae,Lamiaceae,and Moraceae(3.5%each).five plant communities were *** to the results from ordination analysis,the floristic composition of these plant communities was significantly affected by altitude,slope,sand,silt,soil organic matter,total nitrogen,and *** vegetation structure reveals that a large number of individual species was categorized in the lower DBH,frequency,and height *** highest Shannon diversity index and evenness values of the study area were 4.21 and 0.95,*** leiocarpa,Combretum hartmannianum,Ziziphus mucronata,Terminalia macroptera,and Acacia polyacantha were the species with high *** endemic plants were in the IUCN red list categories of Ethiopia and *** o

关键词： Diversity Dryland Hirmi woodland Regeneration status Plant communities

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Modeling Global and Local Aspects of Spatial Structure Explicitly in Land-Use Optimization: The Case of Mek'ele City, Ethiopia

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Chinese Journal of Urban and Environmental Studies 2023年第2期11卷 66-96页

作者： Ashenafi mehari Paolo Vincenzo GENOVESE School of Architecture Tianjin University International Center of History Critics of Architecture and Restoration of Historical Heritage (ICHCR) College of Civil Engineering and Architecture Zhejiang University

Urban spatial structure remains the center of quest and modeling. The decentralization concept is among the leading literature discourses that guide spatial analyses. In line with the decentralization discourse, the application of land-use optimization as a modeling method has grown significantly. Despite decentralization dominating the contemporary spatial analysis literature, no study so far explicitly declares an end to the centers(and subcenters). While centers(and subcenters) are alive, the land-use optimization has never taken this macro-morphological structure into consideration. This case study frames land-use optimization within the agglomeration and decentralization concepts based on the view that no single conceptual framework addresses spatial analysis sufficiently. On a theoretical level, the link is between coarse morphological assumption(basis of economic geography) and decentralization(basis of sustainable built environment). The paper blends these dual theories, one governing urban macro-morphological structures and the other governing decentralization literature. On a methodological modeling level, it blends centers and other discretized uses. Optimizing four objectives across the complete centralization through multiple centers of gravity to complete the decentralization of urban spatial structures applying Non-dominated Sorting Genetic Algorithm II, the case study findings justify the importance of explicit modeling of the macro-morphological element. It has been observed that multicenter urban forms perform well above both the single center and the dispersed scenarios. It is, therefore,argued that an appropriate approach to land-use optimization is modeling both the macro-spatial element and fine spatial elements. The result further indicates that local land-use planning regulations place the structure of city in a suboptimal state.

关键词： Land-use optimization urban form multicenter city decentralization coarse spatial scale fine spatial scale

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Titanium effect on the microstructure and properties of laminated high boron steel plates

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International Journal of Minerals,Metallurgy and Materials 2015年第5期22卷 492-499页

作者： Lin-lin Yuan Jing-tao Han Jing Liu Dong-bin Wei mehari Zelalem Abathun School of Materials Science and Engineering University of Science and Technology Beijing School of Electrical Mechanical and Mechatronic Systems University of TechnologySydney

High-boron steel is an important material used for thermal neutron shielding. The appropriate amount of added boron must be de- termined because excessive boron may deteriorate the steel＇s workability. A uniform microstructure can be formed by adding titanium to boron steel. In this study, casting and hot rolling were used to fabricate laminated high-boron steel plates whose cores contained 2.25wt% boron and 0wt%-7.9wt% titanium. The effects of titanium content and hot-rolling and heat-treatment processes on the microstructure and properties of the laminated plates were studied. The results indicated that the optimum titanium content was 5.7wt% when the boron content was 2.25wt%, and that the best overall properties were obtained after heat treatment at 1100℃ for 4 h. The tensile strength, yield strength, and elongation at the specified temperature and holding time were as high as 526.88 MPa, 219.36 MPa, and 29%, respectively.

关键词： boron steel laminated materials titanium boride hot rolling heat treatment

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The Need for Agricultural Water Management in Sub-Saharan Africa

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Journal of Water Resource and Protection 2016年第9期8卷 835-843页

作者： Kbrom Ambachew Gebrehiwot mehari Gidey Gebrewahid Department of Water Resources and Irrigation Engineering Institute of Technology Haramaya University Haramaya Ethiopia

This paper discusses the current and future conditions that affect water resources and the constraints of water (agricultural) management in sub-Saharan Africa and suggests remedial measures to be considered by policy makers. The pressure on the quantity and quality of water resources is rising in sub-Saharan Africa due to the increased demand of water for agriculture and other purposes as a result of increase in population and food demand. The availability of water is also under threat from changing climate and as a result, water scarcity is expected in many countries in sub-Saharan Africa. On the other hand, the availability of water for agriculture is expected to further shrink due to the increasing demand of water for other purposes like industry, manufacturing and environmental requirement. The current poor efficiency rate of irrigation systems and massive expansion of irrigated area is expected to further exacerbate the water scarcity. Hence, a water management policy focused on maximization of water use efficiency and water productivity should be prioritized in order to meet the food demand of the growing population and cope with water scarcity problems. Engineering and management intervention integrated with strong society awareness and participation is considered very crucial in enhancing water use efficiency and crop water productivity.

关键词： Water Scarcity Water Management Water Use Efficiency Water Productivity Sub-Saharan Africa

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Trace and Macro Elements Concentrations in Selected fresh fruits, Vegetables, Herbs, and Processed foods in North Carolina, USA

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Journal of Environmental Protection 2015年第6期6卷 573-583页

作者： Tsdale f. mehari LaVana Greene A’ja L. Duncan Sayo Olawale fakayode Department of Chemistry North Carolina A&T State University Greensboro NC USA

fresh fruits, vegetables, herbs, and processed foods continue to be the major sources of essential trace elements in humans’ diet required for proper body development. However, food products can potentially be contaminated by toxic heavy metals (HMs) from environmental contamination or industrial food processing. The deleterious health implications of essential trace and macro elements’ deficiency and toxic consequences of HMs in humans necessitate proactive monitoring of the essential trace elements and HMs concentrations in the humans diet to ensure public health safety. Accordingly, this study investigated a comparative analysis of essential elements and potential toxic HMs concentration in food products in the Greensboro metropolis, North Carolina, USA. A total of 49 food samples comprising of 16 difference fresh fruits, 17 fresh vegetables, 4 herbs, and 12 processed foods were purchased from local grocery stores and analyzed for iron (fe), calcium (Ca), magnesium (Mg), nickel (Ni), zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd), and chromium (Cr) by the use of flame atomic absorption spectrometry (fAAS). The concentrations of elements were subjected to a regression analysis to further gain insight of the inter-element association in the food samples. The results of the study showed high variability in the concentrations of elements in the fresh fruits, vegetables, herbs, and processed foods. The overall average concentrations of Ca (1501 μg/g), Mg (186.5 μg/g), fe (55.8 μg/g), Zn (22.2 μg/g), Pb (10.2 μg/g), Cu (5.8 μg/g), Cr (food samples categories. The elements concentrations were generally poorly correlated in the food samples. However, a strong inter-element association between Cu and fe concentration (R2 = 1.000) and a weak association between Ca and fe (R2 = 0.5609) were found in the food samples. A survey questionnaire was administered to 396 participants in the Greensboro metropolis

关键词： foods Trace-Elements-Analysis Atomic-Absorption Spectroscopy Inter-Element-Association Daily/Weekly-Dietary Intake Estimate foods-Consumption-Pattern-Recognition

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高中生纪律问题的成因及其干预策略厄立特里亚的教训

高中生纪律问题的成因及其干预策略厄立特里亚的教训

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作者： Desbele Tekie mehari 华中师范大学

学位级别：硕士

在过去的20年里,厄立特里亚的高中一直面临着学生纪律问题日益严重的挑战,学校的利益相关者对这个问题相互指责推诿。因此,本研究旨在探究导致高中生纪律问题的原因,以及探讨学校与利益相关者合作的可能的干预措施。研究人员从厄立特里... 详细信息

在过去的20年里,厄立特里亚的高中一直面临着学生纪律问题日益严重的挑战,学校的利益相关者对这个问题相互指责推诿。因此,本研究旨在探究导致高中生纪律问题的原因,以及探讨学校与利益相关者合作的可能的干预措施。研究人员从厄立特里亚南部地区选取五所中学,以这些学校的校长、教师、家长（目前为PTSA（家长-老师-学生协会）成员）、学生和学校辅导员为研究对象,采用定性研究方法,使用半结构化访谈和焦点小组讨论收集相关数据。研究人员在与当地前主管部门的合作下,进行了彻底的调查、编码和数据整理工作,以探索数据中出现的主体因素,然后使用自上而下或与主体因素相关的理论方法对数据进行分析。研究发现三个重要主体是影响学生纪律问题的主要因素（即学生相关因素、家庭相关因素和学校相关因素）的来源。研究发现,在教学实践中,每一个利益相关者都有导致学生纪律问题的责任。学校采用不同的方法来预防或避免学生出现纪律问题,研究结果也揭示了学校采取的一些无效的纪律策略。学校的利益相关者对学生违纪问题成因的认识,最终将有利于制定有效的避免和预防学生违纪行为的策略。此外,研究结果还表明,学生、教师、家长以及其他利益相关者在学科规划和实施阶段的参与,可以有效预防以及避免学校纪律问题,而鼓励各方积极参与正是学校校长的责任。

关键词：影响因素纪律问题干预策略

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福清湾、沙埕湾和诏安湾水质趋势评价（2007-2012）

福清湾、沙埕湾和诏安湾水质趋势评价（2007-2012）

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作者： fana mehari Hagos 厦门大学

学位级别：硕士

干净、安全以及充足的水对于地球上生物生存,乃至生态系统平衡、人类居住环境和社会经济运行都有至关重要的作用。随着人口的增长,工农业的扩张以及全球气候的变化,自然界的水循环已经发生了很大的改变。水质下降已成为一个全球性问题,... 详细信息

干净、安全以及充足的水对于地球上生物生存,乃至生态系统平衡、人类居住环境和社会经济运行都有至关重要的作用。随着人口的增长,工农业的扩张以及全球气候的变化,自然界的水循环已经发生了很大的改变。水质下降已成为一个全球性问题,浪费与缺乏有效的管理机制进一步加剧了水资源的退化。水资源问题是如此复杂和多样化,理应引起全世界的注意并采取具体行动。本文研究了福清湾、沙埕湾和诏安湾近年来的海水质量变化情况,结合当前中国现行的海水质量标准以提出保护海洋环境的建议。本文所涉及的海水质量检测是从2007年5月开始至2012年9月结束,其中包括了对营养盐,石油烃类以及重金属的检测。研究的水质参数具体有溶解氧、化学需氧量、活性磷酸盐,亚硝酸盐氮、硝酸盐氮、铵盐氮、石油烃、铜、铅、锌、铬、汞和砷。通过对海水质量评估,笔者发现这三个海湾都存在着不同程度的富营养化风险。福清湾和沙埕湾的海水中有较高浓度的营养盐(特别是硝酸盐氮和活性磷酸盐),造成此结果的原因可能是大量水产养殖场的出现、周边地区的农业活动以及工业废弃物的排放。诏安湾海水则出现了较高含量的活性磷酸盐,这很可能是因为工业废气的排放以及含磷清洁剂和肥料的大量使用。但是根据中国现行的海水质量标准,以上港湾的水质均属于2级水质,仍然属于良好的水平。中国政府已经采取了措施抑制污染物向海洋环境排放。定期检查陆地的污染源,提高政府对主要污染物排放的监管力度是保护海洋生态环境以及水体健康的有效措施。

关键词：水质变化趋势福清湾沙埕湾诏安湾管理

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影响厄立特里亚国际旅游流入因素的研究

影响厄立特里亚国际旅游流入因素的研究

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作者： mehari Gebremeskel Gebrehiwet 江西财经大学

学位级别：硕士

旅游业是当今世界上最具经济活力的行业之一。它正在成为各国的主要的收入来源并不断地给各国创造就业机会。厄立特里亚具有自然、历史和文化所赋予的巨大旅游潜力。尽管具有这些潜力,厄立特里亚也无法充分开发旅游业并从中获益。在厄... 详细信息

旅游业是当今世界上最具经济活力的行业之一。它正在成为各国的主要的收入来源并不断地给各国创造就业机会。厄立特里亚具有自然、历史和文化所赋予的巨大旅游潜力。尽管具有这些潜力,厄立特里亚也无法充分开发旅游业并从中获益。在厄立特里亚,旅游业的收入微不足道,而其业绩不佳的原因并未被全面地研究探讨过。各种国内和国际的研究将其归因于该行业的低绩效。本文将通过探索,介绍和调查厄立特里亚的旅游潜力来分析目的地旅游流入的决定因素。利用目的地竞争力分析模型,重点考察了决定厄立特里亚旅游客源流入的变量。该研究基于与该模型相关的指标结果分析,以确定影响厄立特里亚作为旅游目的地的旅游流入的因素。研究者采用描述性和经验性研究设计,通过采用均值、标准差、曲线图等方法对结果进行分析。在本研究中,一手数据和二手数据都被用于分析。一手数据收集了从分发提问者到旅游服务提供者(利益相关者)和文化事务局以及与旅游官员部的访谈。二手数据来自厄立特里亚旅游局的书面文件、不同的相关研究、书籍、出版和未出版的文件。研究分析表明,政治稳定性差(与埃塞俄比亚的边境战争)和不适当的旅游投资环境是影响厄立特里亚旅游流入的主要决定因素。西方国家对厄立特里亚的不良形象以及联合国安理会和美国对厄立特里亚实施的不公正制裁也阻碍了该国旅游业的发展。该调查还显示,除在旅游资源,管理和情境条件等方面评价较高外,厄立特里亚可继承的旅游资源禀赋优于创建的资源。但是大多数因素的评级低于非洲标准,因此为了促进旅游业的发展,政府需要为此做出很大的改进并且给予特别的关注。

关键词：文化禀赋目的地竞争力旅游目的地管理

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