检索结果-南通市图书馆

Diversity, regeneration status and population structure of gum-and resin-bearing woody species in south Omo zone, southern Ethiopia

引用

journal of Forestry Research 2014年第2期25卷 319-328页

作者： Muhamed Adem Adefires Worku Mulugeta Lemenih Wubalem Tadesse jürgen Pretzsch Madawalabu University Technical University of Dresden Institute of International Forestry and Forest Products Wondo Genet College of Forestry and Natural Resources Ethiopian Institute of Agricultural Research Forestry Research Sector

South Omo Administrative Zone in Ethiopia is home to 18 indigenous ethnic groups whose livelihood is vulnerable due to recurrent drought and degradation. Despite the preliminary observation showing the rich dry-forest resource base that, if sustainably managed could enhance livelihoods and biodiversity conservation, there is lack of empirical data on its current status. We conducted a study aiming at quantifying the population status of gum- and resin-bearing species in two randomly selected districts, Hamer and Bena-Tsemay. Seventy-five quadrats （35 at Hamer and 40 at Bena-Tsemay） each measuring 400 m2 were established along line transects to assess species diversity and equitability, density, frequency, dominance, importance value and population structure. We recorded a total of 27 woody species of 12 families and 14 genera. Fifteen species （9 at Hamer and 14 at Bena-Tsemay） of the genera Acacia, Boswellia, Commiphora and Sterculia, were identified as either major sources of commercial gums and resins or their adulterants. Gum- and resin-bearing species comprised 56% and 57% of species richness, 48% and 50% of total density per ha, 95% and 98% of basal area, and 64% and 56% of importance values at Hamer and Bena-Tsemay, respectively. Diversity of the entire woody species assemblage and of the gum- and resin-bearing species was slightly higher at Bena-Tsemay （H= 2.61, 1.4） than at Hamer （H＇= 2.48, 1.28）, respectively. The diversity and abundance of the resource base suggest potential for development of value-added commercialization of gum and resins to enhance livelihoods and encourage sustainable management of the forest at these study areas. We recorded, however, declining natural regeneration of most gum- and resin-bearing species, and this calls for integrated and participatory species management and landscape rehabilitation.

关键词： Acacia Boswellia Commiphora Sterculia gum and resins population status southern Ethiopia

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chatter identification of thin-walled parts for intelligent manufacturing based on multi-signal processing

引用

Advances in Manufacturing 2021年第1期9卷 22-33页

作者： Dong-Dong Li Wei-Min Zhang Yuan-Shi Li Feng Xue jürgen Fleischer school of Mechanical Engineering Tongji UniversityShanghai 201804People's Republic of China Bosch Rexroth Endowed Chair for Automation&Electrification Solutions Sino-German College for Postgraduate StudyTongji UniversityShanghai 201804People's Republic of China China North Engine Research Institute Tianjin 300400People's Republic of China WBK Institute of Production Science Karlsruhe Institute of TechnologyKarlsruhe 76131Germany

Machine chatter is still an unresolved and challenging issue in the milling process,and developing an online chatter identification and process monitoring system towards smart manufacturing is an urgent *** this paper,two indicators of chatter detection are *** is the real-time variance of milling force signals in the time domain,and the other one is the wavelet energy ratio of acceleration signals based on wavelet packet decomposition in the frequency ***,a novel classification concept for vibration condition,called slight chatter,is proposed and integrated successfully into the designed multi-classification support vector machine(SVM)***,a mapping model between image and chatter indicators is established via a distance threshold on the *** multi-SVM model is trained by the results of three signals as an *** data and detection accuracy of the SVM model are verified in actual *** identification accuracy of 96.66%has proved that the proposed solution is feasible and *** presented method can be used to select optimized milling parameters to improve machining process stability and strengthen manufacturing system monitoring.

关键词： Chatter Milling force Acceleration Wavelet packet decomposition Multi-sensor

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cuticular hydrocarbons in two parapatric species of ants and their hybrid

引用

Integrative Zoology 2011年第3期6卷 259-265页

作者： Mohamed EL-SHEHABY Mohamed Sayed SALAMA Elisabeth BRUNNER jürgen HEINZE Biologie I University of RegensburgRegensburgGermany Department of Entomology Ain Shams UniversityCairoEgypt

Discrimination between nestmates and non-nestmates in social insects is thought to rely on the pattern of cuticular *** investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species,Temnothorax nylanderi(Förster,1850)and Temnothorax crassispinus(Karavaiev,1926),and their *** found that although the profiles show considerable similarities,a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 *** profiles of hybrids were not consistently intermediate between those of the paternal species,suggesting either non-additive interactions among the parental biosynthetic pathways or systematic differ-ences in environment-derived odor cues.

关键词： colony odor cuticular hydrocarbons hybridization Temnothorax

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The impact of salps(Salpa thompsoni)on the Antarctic krill population(Euphausia superba):an individual-based modelling study

引用

Ecological Processes 2023年第1期12卷 680-695页

作者： Bruno Walter Pietzsch Aaron schmidt jürgen Groeneveld Dominik Bahlburg Bettina Meyer Uta Berger Faculty of Environmental Sciences Institute of Forest Growth and Forest Computer SciencesTechnische Universität Dresden01062 DresdenGermany Department of Ecological Modelling Helmholtz Centre for Environmental Research-UFZLeipzigGermany Section Polar Biological Oceanography Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchBremerhavenGermany Institute for Chemistry and Biology of the Marine Environment(ICBM) Carl-Von-Ossietzky UniversityOldenburgGermany Helmholtz Institute for Marine Functional Biodiversity(HIFMB) OldenburgGermany

Background Krill(Euphausia superba)and salps(Salpa thompsoni)are key macrozooplankton grazers in the Southern Ocean ***,due to differing habitat requirements,both species previously exhibited little spatial *** ongoing climate change-induced seawater temperature increase and regional sea ice loss,salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are *** the potential effects on krill is crucial,since krill is a species of exceptional trophic significance in the Southern Ocean food *** impacts on krill could trigger cascading effects on its predators and *** address this question,we combined two individual-based models on salps and krill,which describe the whole life cycle of salp individuals and the dynamic energy budget of individual *** resulting new model PEKRIS(PErformance of KRIll ***)simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of *** All of the investigated krill population properties(abundance,mean length,and yearly egg production)were significantly impacted by the presence of *** the other hand,salp density was not impacted if krill were *** medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by−99.9%(−234 individuals per 1000 m3)for krill density,−100%(−22,062 eggs per 1000 m3)for krill eggs and−0.9%(−0.3 mm)for mean length of *** If both species compete for the same food resource in a closed space,salps seem to inhibit krill *** simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are ***,direct predation of the two species or consumption of krill fecal pellets by salps could c

关键词： Euphausia superba Salpa thompsoni Individual-based model Food competition Population dynamics DEB theory

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Neuroprotection by resveratrol-glucuronide and quercetin-glucuronide via binding to polyphenol-and glycosaminoglycan-binding sites in the laminin receptor

引用

Neural Regeneration Research 2025年第3期20卷 819-820页

作者： Rayudu Gopalakrishna jennifer Aguilar Emily Lee William j.Mack Department of Integrative Anatomical Sciences Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCAUSA Department of Neurological Surgery Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCAUSA

The dietary polyphenolic compounds resveratrol and quercetin prevent neurodegenerative diseases in experimental models;however, they reach the brain only in nanomolar concentrations in the glucuronidated and sulfated ... 详细信息

关键词： resveratrol molar dated

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Extra-pair paternity and antiparasitic defence

引用

Avian Research 2020年第4期11卷 391-397页

作者： Anders Pape Møller jørgen Skavdal Søraker juan joséSoler Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering College of Life SciencesBeijing Normal UniversityBeijing 100875China Ecologie Systématique et Evolution UniversitéParis-SaclayCNRSAgroParisTech91405 OrsayFrance Centre for Biodiversity Dynamics Department of BiologyNorwegian University of Science and TechnologyHøgskoleringen 5No-7491TrondheimNorway Depto.Ecología Funcional y Evolutiva Estación Experimental de ZonasÁridasCtra.Sacramento S/NLa Cañada de San Urbano04120 AlmeríaSpain

Background:Extra-pair paternity(EPP)in birds provides benefits in terms of more offspring,and characteristics for maintenance of this behaviour have been the subject of *** are known to be transmitted during mating,especially when mating with multiple partners,and factors reducing this cost of multiple mating are ***,plumage brightness and colour intensity have been shown to be important traits to benefits from multiple mating as predicted by sexual *** aim of this study was to investigate the relationship between the rate of extra-pair paternity and the relative size of the uropygial gland at the interspecific level,as the uropygial gland is an exocrine gland hypothesized to produce antiparasitic substances and further identified to affect plumage *** of the expected benefits of large uropygial gland in scenarios of sexual selection,we predicted a positive correlation with ***:We collected information from the literature of uropygial gland size and frequency of extra-pair paternity of 60 avian species of different families and explored the predicted positive correlation between *** did so with means of comparative analyses that considered phylogenetic relationship as random factor and included body mass as *** used Markov chain Monte Carlo generalized linear mixed models that were weighted by number of nests used to estimate extra-pair ***:We detected a positive relationship between level of extra-pair paternity and uropygial gland size at an interspecific *** finding is consistent with the ***:We discuss the importance of this result in scenarios of sexual selection and argue that the detected relationship may have arisen by utilizing antiparasitic secretions through secondary sexual characters indicating parasite resistance.

关键词： Antiparasitic defence Costs of extra-pair paternity Microorganisms Uropygial gland Uropygial secretions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nonsingularity of Grain-like cascade FSRs via semi-tensor product

引用

Science China(Information Sciences) 2018年第1期61卷 58-69页

作者： jianquan LU Meilin LI Yang LIU Daniel W.C.HO jrgen KURTHS school of Mathematics Southeast University College of Mathematics Physics and Information Engineering Zhejiang Normal University Department of Mathematics City University of Hong Kong Potsdam Institute for Climate Impact Research

In this paper, Grain-like cascade feedback shift registers(FSRs) are regarded as two Boolean networks(BNs), and the semi-tensor product(STP) of the matrices is used to convert the Grain-like cascade FSRs into an equivalent linear equation. Based on the STP, a novel method is proposed herein to investigate the nonsingularity of Grain-like cascade FSRs. First, we investigate the property of the state transition matrix of Grain-like cascade FSRs. We then propose their sufficient and necessary nonsingularity condition. Next,we regard the Grain-like cascade FSRs as Boolean control networks(BCNs) and further provide a sufficient condition of their nonsingularity. Finally, two examples are provided to illustrate the results obtained in this paper.

关键词： Grain-like cascade FSRs Boolean control networks Boolean networks semi-tensor product nonsingularity

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

在人体和动物烧伤皮肤中产生的毒素对离体鼠肝细胞的影响

引用

国际外科学杂志 1981年第3期8卷 168-170页

作者： schlmerich j 裘华德

近100年来,曾多次提出严重烧伤时存在一种毒性因子的可能性。1975年schoenenberger终于成功地由烧伤的鼠皮以及严重烧伤患者的皮肤和血清中提取出一种对实验动物有致死毒性作用的脂蛋白复合物。研究发现,这种毒素对肝细胞有较强的亲和力... 详细信息

近100年来,曾多次提出严重烧伤时存在一种毒性因子的可能性。1975年schoenenberger终于成功地由烧伤的鼠皮以及严重烧伤患者的皮肤和血清中提取出一种对实验动物有致死毒性作用的脂蛋白复合物。研究发现,这种毒素对肝细胞有较强的亲和力,它可以使鼠肝细胞的超微结构发生和烧伤时相似的变化。作者也在实验中证实,给予毒素后,离体鼠肝的物质代谢和超微结构变化,与皮肤烧伤后的变化均很相似。

关键词：鼠肝细胞物质代谢前体毒素毒物离体皮肤解剖部位动物

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Fundamentals of Visualizing Communication Networks

引用

China Communications 2013年第3期10卷 82-90页

作者： jürgen Pfeffer school of Computer Science Carnegie Mellon University

The human brain is built to process complex visual impressions within milliseconds. In comparison with sequentially coded spoken language and written texts, we are capable of consuming graphical information at a high bandwidth in a parallel fashion, producing a picture worth more than a thousand words. Effective information visualization can be a powerful tool to capture people's attention and quickly communicate large amounts of data and complex information. This is particularly important in the context of communication data, which often describes entities (people, organizations) and their connections through communication. Visual analytics approaches can optimize the user-computer interaction to gain insights into communication networks and learn about their structures. Network visualization is a perfect instrument to better communicate the results of analysis. The precondition for effective information visualization and successful visual reasoning is the capability to draw "good" pictures. Even though communication networks are often large, including thousands or even millions of people, underlying visualization principles are identical to those used for visualizing smaller networks. In this article, you will learn about these principles, giving you the ability to assess the quality of network visualizations and to draw better network pictures by yourself.

关键词： communication networks information visualization human perception

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New para-magnetic(CoFeNi)(50)(CrMo)(50-x)(CB)x(x=20,25,30)non-equiatomic high entropy metallic glasses with wide supercooled liquid region and excellent mechanical properties

引用

journal of Materials Science & Technology 2020年第8期36卷 135-143页

作者： jeong Tae Kim Sung Hwan Hong jin Man Park jürgen Eckert Ki Buem Kim Erich schmid Institute of Materials Science Austrian Academy of Sciences(ÖAW)Jahnstrae 128700LeobenAustria Hybrid Materials Center(HMC) Department of Nanotechnology and Advanced Materials EngineeringSejong University209Neungdong-roGwangjin-guSeoul143-747Republic of Korea Global Technology Center(GTC) Samsung Electronics Co.Ltd129 Samsung-roYeongtong-guSuwonsiGyeonggi-do443-742Republic of Korea Department of Materials Science Chair of Materials PhysicsMontanuniversität LeobenJahnstraße 128700LeobenAustria

In this study,high entropy metallic glasses(HEMGs)were developed through a combination of concepts for designing metallic glasses(main element+transition metal+metalloid element)and high-entropy alloys(more than five elements,each element having an atomic concentration between 5 at.%and 35 at.%).The developed metallic glass alloys are composed of Co-Fe-Ni main elements,transition metals(Cr,Mo)and metalloid elements(C,B).Moreover,the present work reports the thermal,mechanical and magnetic properties of(CoFeNi)(50)(CrMo)(50-x)(CB)x alloys with x=20,25,*** developed as-spun HEMGs exhibit typical paramagnetic properties even for a high amount of ferromagnetic elements(Co,Fe,and Ni)and have high elastic modulus(103–160 GPa)and hardness(14–27 GPa),thus possessing mechanical properties similar to well-known Co-based metallic glasses(Co-Cr-Mo-C-B system).In addition,some of the bulk samples prepared with a diameter of 2 mm form bulk metallic glasses with a high compressive strength around 3.5 *** mechanisms determining the stability of the supercooled liquid,as well as the paramagnetic and mechanical properties for the developed non-equiatomic HEMGs,are discussed.

关键词： Metallic glasses Paramagnetism High entropy alloys Phase stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：