检索结果-南通市图书馆

Pedosphere 2012年第2期22卷 225-229页

作者： s.D.VEREsOgLOU Faculty of Agriculture Laboratory of Ecology and Environmental ProtectionAristotle University of Thessaloniki

The vast majority of herbaceous plants engage into arbuscular mycorrhizal (AM) symbioses and consideration of their mycorrhizal status should be embodied in studies of plant-microbe interactions. To establish reliable AM contrasts, however, a sterilized re-inoculation procedure is commonly adopted. It was questioned whether the specific approach is sufficient for the studies targeting the bacterial domain, specifically nitrifiers, a group of autotrophic, slow growing microbes. In a controlled experiment mycorrhizal and non-mycorrhizal Plantago lanceolata were grown up in compartmentalized pots to study the AM effect on nitrification rates in the plant rhizosphere. Nitrification rates were assayed following an extensive 3-week bacterial equilibration step of the re-inoculated soil and a 13-week plant growth period in a controlled environment. Under these specific conditions, the nitrification potential levels at harvest were exceptionally low, and actual nitrification rates of the root compartment of non-mycorrhizal P. lanceolata were significantly lower than those of any other compartment. It is then argued that the specific effects should be attributed to the alleged higher growth rates of non-mycorrhizal plants that are known to occur early in the AM experiment. It is concluded that the specific experimental approach is not suitable for the study of microbes with slow growth rates.

关键词： ammonia oxidizers nitrification potential plant-microbe interaction root compartment

Factors determining the occupancy of nest-boxes by great Tits(Parus major)in eucalypt plantations

在线全文

学校读者我要写书评

暂无评论

Avian Research 2023年第2期14卷 200-205页

作者： Ricardo s.Ceia Pedro B.Lopes Luís Pda silva Centre for Functional Ecology–science for People&the Planet Department of Life SciencesUniversity of Coimbra3000-456CoimbraPortugal CIBIO Centro de Investigaçao em Biodiversidade e Recursos GeneticosInBIO Laboratorio AssociadoCampus de Vair aoUniversidade do Porto4485-661VairaoPortugal BIOPOLIs Program in genomics Biodiversity and Land PlanningCIBIOCampus de Vai~ao4485-661VairaoPortugal

Providing nest-boxes as surrogate tree cavities can be of great importance to increase the breeding populations of cavity-nesting birds in managed ***,the exact placement of nest-boxes should be taken into consideration to enhance their occupancy according to species-specific *** this study,we investigated which factors can better predict nest-box occupancy by the great Tit(Parus major)in eucalypt *** used generalised linear mixed-effects models to analyse the influence of topography,nest-box positioning,vegetation cover and landscape variables on three-year occupancy records from 80 newly provided ***-random patterns of nest-box occupancy were found with respect to all categories except *** suggest that great Tits prefer to occupy high-placed nest-boxes,close to areas that can provide them with supplementary resources either within or in the vicinity of the stand(i.e.,trees other than eucalypts,riparian vegetation,and large patches of adjacent habitats).Overall,this study provides important recommendations for nest-box placement and spatial distribution in managed forests and enhances the potential of nest-box interventions as a biodiversity offset and management tool.

关键词： Eucalyptus globulus Managed forest Nest-site attributes secondary cavity-nester species-specific preferences Tit

Peristaltic flow of Walter’s B fluid in endoscope

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2011年第6期32卷 689-700页

作者： s.NADEEM N.s.AKBAR T.HAYAT A.A.HENDI Department of Mathematics Quaid-i-Azam University Department of Physics Faculty of ScienceKing Saud University

The peristaltic flow of a Walter＇s B fluid in an endoscope is studied. The problem is modeled in a cylindrical coordinate system. The main theme of the present analysis is to study the endoscopic effects on the peristaltic flow of the Waiter＇s B fluid. To the best of the authors＇ knowledge, no investigation has been made so far in the literatures to study the Walter＇s B fluid in an endoscope. Analytical solutions axe obtained using the regular perturbation method by taking 5 as a perturbation parameter. The approximate analytical solutions for the pressure rise and friction forces are evaluated using numerical integration. The effects of emerging parameters of the Waiter＇s B fluid are presented graphically.

关键词： peristaltic flow Walter's B fluid endoscope perturbation solution.

在线全文

学校读者我要写书评

暂无评论

锌-三氧化二铬复合镀层的特性(英文)

电镀与涂饰 2011年第9期30卷 12-15页

作者： KARTHIKEYAN s VENKATACHALAM g NARAYANAN s sRINIVAsAN K N Materials Division SASVIT UniversityVellore-632014India

采用由氧化锌 12 g/L、氢氧化钠 94 g/L、2-氨基-3-羧基吡啶 4.2 g/L、四乙烯五胺 17 g/L、三乙醇胺 2 g/L、专利表面活性剂0.5 g/L及碳三氧化二铬(粒径2 μm)0 ～ 11 g/L组成的镀液,于温度 50 °C、pH 6.5 和电流密度 4 A/dm2的条件下... 详细信息

采用由氧化锌 12 g/L、氢氧化钠 94 g/L、2-氨基-3-羧基吡啶 4.2 g/L、四乙烯五胺 17 g/L、三乙醇胺 2 g/L、专利表面活性剂0.5 g/L及碳三氧化二铬(粒径2 μm)0 ～ 11 g/L组成的镀液,于温度 50 °C、pH 6.5 和电流密度 4 A/dm2的条件下,在低碳钢上电镀 Zn-Cr2O3复合镀层。其显微硬度采用维氏硬度计测量,耐磨性用 Taber 磨耗试验机测量,表面形貌和显微组织采用扫描电镜(sEM)、X 射线衍射(XRD)及 X 射线光电子能谱(XPs)进行分析,在 3.5%(质量分数)NaCl 溶液中的耐蚀性以电化学阻抗谱(EIs)评价。证实了锌基体中存在团聚的 Cr2O3颗粒。与纯锌镀层相比,Zn-Cr2O3复合镀层的机械性能及耐蚀性能更好。

关键词：锌三氧化二铬复合镀层耐蚀性显微硬度耐磨性

TCR-pMHC: may the force be of you?

在线全文

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2021年第7期18卷 1622-1623页

作者： Joseph s.Murray Xenolaüs genetics LLC Los AngelesCA90024USA

Theα/βcomponent of the T-cell antigen receptor(TCR)is a transmembrane heterodimer containing genetically variable(V)domains and constant domains within each polypeptide chain.1 The Vαand Vβdomains bind with a clonally unique(clonotypic)interface angle,2 and the complementary determining regions(CDR1,CDR2,and CDR3)manifest as‘loops’between anti-parallelβ-strands of the overall sandwich ofβ-sheets with a central disulfide *** with immunoglobulins,the CDR1 and CDR2 loops are encoded in the germline via the particular V-region DNA segment involved in the RAg1/RAg2 recombination mechanism responsible for somatic construction,together with the D-and/or J-segment,of the third loop,CDR3.1,3 As shown by multiple solved X-ray crystallography structures,the CDRs contain the closest amino acid(a.a.)contacts with the peptide(p)plus the major histocompatibility complex(MHC)protein(together abbrev.,pMHC)composite *** rigorous selection in the thymus for only those TCRs that should function properly in the particular individual after birth(MHC restriction),4 T cells function clonally as well,i.e.,different T-cell clones display differential responses to not only different pMHC ligands but also perhaps more importantly,to the same pMHC ligands.5,6 A long-standing question is how(not whether)TCR V-domain binding to pMHC is ultimately responsible for such vast biological outcomes as protection *** to infectious diseases,atopy,the onset of autoimmune diseases,and the success of various types of transplantation.

关键词： properly sandwich rigorous

Mapping forest fires by nonparametric clustering analysis

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

Journal of Forestry Research 2018年第1期29卷 177-185页

作者： Bulent Tutmez Mert g.Ozdogan Ahmet Boran school of Engineering Inonu University Malatya 44280Turkey Regional Directorate of Forestry Antalya 07540 Turkey

Fires have a noteworthy role to play with regards to ecological and environmental losses in Mediterranean forests. In addition to ecological impacts, fire may create economic, social as well as cultural changes. The detection of fire-scars has critical importance to help decrease *** the present study, forest fires recorded in Antalya, one of the most important ecological and tourist regions within the Western Mediterranean, were clustered and mapped. since the dominant factors and devastation records derived from the cases had nominal-scaled properties, a categorical databased nonparametric clustering algorithm was performed in this evaluation. The proposed tool, k-modes algorithm,uses modes instead of means for clustering. The algorithm may be implemented quickly and does not make distributional assumptions concerning the available data. It uses a frequency-based method to update the modes of the *** derived modes from the maps may be useful information for local authorities to manage. In conclusion, the proposed nonparametric clustering procedure may be employed to build a decision-support system to monitor and identify fire activities and to enhance fire management efficiency.

关键词： Forest fire Categorical variable Clustering Western mediterranean

在线全文

学校读者我要写书评

暂无评论

最近13万年黄土高原季风变迁的磁化率证据

科学通报 1990年第7期35卷 529-532页

作者：安芷生 s.Porter g.Kukla 肖举乐中国科学院西安黄土与第四纪地质开放研究实验室西安710061 美国华盛顿大学第四纪研究中心美国哥伦比亚大学拉蒙特地质观测所

黄土高原的近代褐土属季风气候条件下的地带性土壤。黄土-古土壤序列中褐土型古土壤和黑垆土的微形态特征及所保存的生物遗存,指示了干湿季节分明和高温与多雨季节相一致的季风气候特点。

关键词：季风磁化率太阳辐射黄土高原

Finite groups with Four Relative Commutativity Degrees

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2015年第3期22卷 449-458页

作者： A. Erfanian M. Farrokhi D.g. Department of Pure Mathematics and Center of Excellence in Analysison Algebraic structures Ferdowsi University of Mashhad Mashhad Iran Department of Pure Mathematics Ferdowsi University of Mashhad Mashhad Iran

It is shown that a finite group g has four relative commutativity degrees if and only if g/Z（g） is a p-group of order p3 and g has no abelian maximal subgroups, or g/Z（g） is a Frobenius group with Frobenius kernel and complement isomorphic to Zp × Zp and Zq, respectively, and the sylow p-subgroup of g is abelian, where p and q are distinct primes.

关键词： relative commutativity degree commutativity degree finite group

Quantization of the O（N） Nonlinear sigma Model

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

Communications in Theoretical Physics 2002年第5期37卷 567-570页

作者： s.I.Muslih DepartmentofPhysics Al－AzharUniversityGazaPalestine

The Hamilton-Jacobi method of quantizing singular systems is discussed. The equations of motion areobtained as total differential equations in many variables. It is shown that if the system is integrable, one can obtain thecanonical phase space coordinates and set of canonical Hamilton-Jacobi partial differential equations without any needto introduce unphysical auxiliary fields. As an example we quantize the O(2) nonlinear sigma model using two differentapproaches: the functional schrodinger method to obtain the wave functionals for the ground and the exited state andthen we quantize the same model using the canonical path integral quantization as an integration over the canonicalphase-space coordinates.

关键词：量子力学 O(N)非线性sigma模型量子化

NOREss台阵远震尾波中体波到面波的散射能量

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

世界地震译丛 1994年第3期25卷 83-88页

作者： g.s.Wagner C.A.Langston

为了测定台阵下面岩石层不均匀性的程度和尺度以及局部散射源的位置,对NOREss地震台阵记录的远震数据进行了分析研究,用相对尾波强度包络、频率-波数谱和质点运动方法分析了数据。尾波强度包络未清楚地显示出ka趋势,但在初动之后15s左... 详细信息

为了测定台阵下面岩石层不均匀性的程度和尺度以及局部散射源的位置,对NOREss地震台阵记录的远震数据进行了分析研究,用相对尾波强度包络、频率-波数谱和质点运动方法分析了数据。尾波强度包络未清楚地显示出ka趋势,但在初动之后15s左右未含有较高能量水平和高能波包的0.5Hz带通数据却表明ka趋势。频率一波数分析表明大多数远震尾波是垂直传播的。以15s左右为中心的时间窗,含有低视速度向东北方向传播的地震能量。时间窗内的质点运动具有瑞雷面波的反向椭圆特征。估计导致体波向面波能量散射的散射源位于台阵西西南方向大约30km的Mjosa湖附近。

关键词：远震尾波体波面波散射能量