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C:N:P stoichiometry and nutrient limitation of the soil microbial biomass in a grazed grassland site under experimental P limitation or exces

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Ecological Processes 2012年第1期1卷 66-76页

作者： Bryan s Griffiths Annette spilles Michael Bonkowski Teagasc Environment Research CentreJohnstown CastleWexfordCoWexfordIreland Current address:sAC King's BuildingsWest Mains RoadEdinburgh EH93JGUK Mathematisch Naturwissenschaftliche Fakultät der Universität zu Köln Zoologisches Institut Abt.TerrestrischeÖkologieBiowissenschaftliches ZentrumOtto-Fischer-Str.6D-50674KölnGermany

Introduction:The availability of essential nutrients,such as nitrogen(N)and phosphorus(P),can feedback on soil carbon(C)and the soil microbial *** cycles can be supplemented by agricultural fertiliser addition,and we determined whether the stoichiometry and nutrient limitation of the microbial biomass could be affected by an unbalanced nutrient ***:samples were taken from a long-term trial(in effect since 1968)with annual applications of 0,15 and 30 kg P ha^(−1) with constant N and *** and microbial biomass CNP contents were measured and nutrient limitation assessed by substrate-induced *** regression and discriminant analyses were used to identify the variables explaining nutrient ***:soil and biomass CNP increased with increasing P fertiliser,and there was a significant,positive,correlation between microbial biomass P and biomass C,apart from at the highest level of P fertilisation when the microbial biomass was over-saturated with *** molar ratios of C:N:P in the microbial biomass remained constant(homeostatic)despite large changes in the soil nutrient *** growth was generally limited by C and N,except in soil with no added P when C and P were the main limiting nutrients.C,N and P,however,did not explain all the growth limitation on the soils with no added ***:Increased soil C and N were probably due to increased net primary *** results confirm that C:N:P ratios within the microbial biomass were constrained(***)under near optimum soil *** with no added P were characterised by strong microbial P limitation and soils under high P by over-saturation of microorganisms with *** changes in biomass C:P can be indicative of nutrient limitation within a site.

关键词： Carbon Nitrogen Nutrient limitation Phosphorus soil microbial biomass stoichiometry

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sexual dimorphism in water and nitrogen use strategies in Honckenya peploides: timing matters

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Journal of Plant Ecology 2017年第4期10卷 702-712页

作者： Julia sánchez Vilas Rubén Retuerto Organisms and Environment Division Sir Martin Evans BuildingCardiff School of BiosciencesMuseum AvenueCardiff UniversityCardiff CF103AXUK Departamento de Biología Celular y Ecología Área de EcologíaFacultad de BiologíaUniversidade Santiago de CompostelaCampus VidaRúa de Lope Gómez de Marzoas/n15782 Santiago de CompostelaA CoruñaSpain

Aims sexes of dimorphic species often differ in ecophysiological traits and display spatial *** differences have been interpreted as an evolved response of the sexes to meet the specific resource demands associated with *** may differ not only in the amount of resources allocated to reproduction but also in the tim-ing of allocation to *** this study,we hypothesize that as a consequence of their specific resource demands for reproduction,the sexes of the dune plant Honckenya peploides differ in terms of tempo-ral patterns of water use efficiency and nitrogen use and *** Water use efficiency,as inferred from leaf carbon isotope discrimi-nation(Δ^(13)C),nitrogen use,estimated by leaf nitrogen isotope com-position(δ^(15)N),and the foliar carbon and nitrogen contents were measured in males and females at three different points in *** Findings Females had greater water use efficiency than males,regardless of *** ratio of N^(15) to N^(14) did not change with time in males,but significantly decreased in August for *** total N content in the leaf tissues of females decreased as the season progressed,while in males a decrease was only found from April to June and then it remained constant from June to August.A similar pattern,but reversed,was followed by the foliar C/N ***,nega-tive relationships between leafΔ^(13)C and N content were found at all times for males and only at the end of the season for ***,our hypothesis that sex-specific patterns of nitrogen and water use efficiency will depend on time was ***,our results highlight the importance of including time in studies of sex-ual dimorphism,and also the role that physiological specialization plays in meeting the specific demands associated with reproduction.

关键词： cost of reproduction Honckenya peploides leaf nitrogen content sexual dimorphism stable isotopes water use efficiency

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上海、纽约股票价格指数的时间序列分析

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经济资料译丛 2004年第4期 54-61,87页

作者： Gregory C.chow Caroline C.Lawler 郭鹏辉厦门大学经济学院计统系 361005

本文旨在研究上海、纽约股票指数的各自特点以及它们的相互关系.上海股票市场是在1992年经济快速发展的背景下建立的(chow,***.1999).以回报率、波动率和可能存在的结构变化来研究上海股市价格指数变动的特点将是饶有兴趣的.将这种特点... 详细信息

本文旨在研究上海、纽约股票指数的各自特点以及它们的相互关系.上海股票市场是在1992年经济快速发展的背景下建立的(chow,***.1999).以回报率、波动率和可能存在的结构变化来研究上海股市价格指数变动的特点将是饶有兴趣的.将这种特点与纽约股票交易价格指数相应的特点进行比较尤为令人感兴趣,因为它们可以揭示一个新生市场股价变动的本质.

关键词：股票价格指数变动上海股票市场上海股市市价股票指数波动率兴趣特点纽约

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Optimal regulation of uncertain dynamic systems using adaptive dynamic programming

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Journal of Control and Decision 2014年第3期1卷 226-256页

作者： Hao Xu Qiming Zhao s.Jagannathan Department of Electrical and Computer Engineering Missouri University of Science and TechnologyRollaMOUSA

In this tutorial paper,the finite-horizon optimal adaptive regulation of linear and nonlinear dynamic systems with unknown system dynamics is presented in a forward-in-time manner using adaptive dynamic programming(ADP).An adaptive estimator(AE)is introduced with the idea of Q-learning to relax the requirement of system dynamics in the case of linear system,while neural network-based identifier is utilised for nonlinear *** time-varying nature of the solution to the Bellman/Hamilton–Jacobi–Bellman equation is handled by utilising a time-dependent basis function,while the terminal constraint is incorporated as part of the update law of the AE/Identifier in solving the optimal feedback *** an initial admissible control,the proposed optimal regulation scheme of the uncertain linear and nonlinear system yields a forward-in-time and online solution without using value and/or policy *** adaptive observer is utilised for linear systems in order to relax the need for state availability so that the optimal adaptive control design depends only on the reconstructed ***,the optimal control is covered for nonlinear-networked control systems where in the feedback loop is closed via a communication *** of the proposed approach is verified by simulation *** end result is a variant of a roll-out scheme in ADP wherein an initial admissible policy is selected as the base policy and the control policy is enhanced using a one-time policy improvement at each sampling interval.

关键词： adaptive dynamic programming finite horizon optimal control

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Modeling of fine coal flotation separation based on particle characteristics and hydrodynamic conditions

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International Journal of Coal science & Technology 2016年第4期3卷 429-439页

作者： B. shahbazi s. Chehreh Chelgani Department of Mining Engineering Tarbiat Modares University Tehran Iran Department of Electrical Engineering and Computer science University of Michigan Ann Arbor MI 48109 USA

Flotation is a complex multifaceted process that is widely used for the separation of finely ground minerals. The theory of froth flotation is complex and is not completely understood. This fact has been brought many monitoring challenges in a coal processing plant. To solve those challenges, it is important to understand the effect of different parameters on the fine particle separation, and control flotation performance for a particular system. This study is going to indicate the effect of various parameters （particle Characteristics and hydrodynamic conditions） on coal flotation responses （flotation rate constant and recovery） by different modeling techniques. A comprehensive coal flotation database was prepared for the statistical and soft computing methods. statistical factors were used for variable selections. Results were in a good agreement with recent theoretical flotation investigations. Computational models accurately can estimate flotation rate constant and coal recovery （correlation coefficient 0.85, and 0.99, respectively）. According to the results, it can be concluded that the soft computing models can overcome the complexity of process and be used as an expert system to control, and optimize parameters of coal flotation process.

关键词： Coal processing Flotation Modeling Particle characteristics - Hydrodynamic conditions

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Non-viral causes of hepatocellular carcinoma

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World Journal of Gastroenterology 2010年第29期16卷 3603-3615页

作者： Wojciech Blonski David s Kotlyar Kimberly A Forde Division of Gastroenterology University of Pennsylvania Department of Gastroenterology Medical University Wroclaw Department of Internal Medicine Montefi ore Medical CenterAlbert Einstein College of Medicine

Hepatocellular carcinoma(HCC) is the most common primary liver malignancy and represents an international public health concern as one of the most deadly cancers *** main etiology of HCC is chronic infection with hepatitis B and hepatitis C ***,there are other important factors that contribute to the international burden of *** these are obesity,diabetes,non-alcoholic steatohepatitis and dietary *** evidence suggests that the etiology of many cases of HCC is in fact multifactorial,encompassing infectious etiologies,comorbid conditions and environmental *** of relevant non-viral causes of HCC will aid in preventative efforts to curb the rising incidence of this disease.

关键词： Hepatocellular carcinoma Etiology Nonalcoholic steatohepatitis Obesity Diabetes Alcohol Tobacco Oral contraceptive

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Analytic Beta-Wavelet Transform-Based Digital Image Watermarking for secure Transmission

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Computers, Materials & Continua 2022年第3期70卷 4657-4673页

作者： Hesham Alhumyani Ibrahim Alrube sameer Alsharif Ashraf Afifi Chokri Ben Amar Hala s.El-sayed Osama s.Faragallah Department of Computer Engineering College of Computers and Information TechnologyTaif UniversityP.O.11099Taif21944Saudi Arabia Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Kom32511Egypt Department of Information Technology College of Computers and Information TechnologyTaif UniversityP.O.11099Taif21944Saudi Arabia

The rapid development in the information technology field has introduced digital watermark technologies as a solution to prevent unauthorized copying and redistribution of *** article introduces a self-embedded image verification and integrity *** images are firstly split into dedicated segments of the same block ***,different Analytic Beta-Wavelet(ABW)orthogonal filters are utilized for embedding a self-segment watermark for image segment using a predefined *** orthogonal filter coefficients are estimated to improve image reconstruction under different block *** conduct a comparative study comparing the watermarked images using three kinds of ABW filters for block sizes 64×64,128×128,and 256×*** embed the watermark using the ABW-based image watermarking method in the 2-level middle frequency sub-bands of the ABW digital image *** imperceptibility and robustness of the ABW-based image watermarking method image is evaluated based on the Peak signal to Noise Ratio(PsNR)and Correlation coefficient *** the implementation results,we came to know that this ABW-based image watermarking method can withstand many image manipulations compared to other existing methods.

关键词： Watermarking ABW median filtering JPEG compression PsNR

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spatial investigation of the temporal urban form to assess impact on transit services and public transportation access

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Geo-spatial Information science 2012年第3期15卷 187-197页

作者： P.N.DADHICH s.HANAOKA Department of International Development Engineering Graduate School of Science&EngineeringTokyo Institute of Technology2-12-1-I4-12OokayamaMeguro-kuTokyo 152-8550Japan

The rapid urban growth in developing city increases the requirement of the efficient and sustainable public transportation *** urban growth affects the urban form,which indicates the change in human and urban development *** form affects directly and indirectly access to the public transportation system as an assessment of potential riders and proximity to stops increase transit services ***,access is one of the important aspects for the assessment of transit service *** transportation access can be represented by a coverage area and useful to estimate potential riders of public *** this study,a Geographical Information system(GIs)-based spatial statistical analysis method is used to examine the spatial relationship of different urban form indicators with population or riders of transit service in a coverage area and to ascertain how urban form influences public transportation trips in this coverage *** coverage area is delineated using a GIs-based road/street network distance *** spatial analysis results suggested that urban forms have certain impact on trips in coverage area at both ward level and zone *** statistical analysis implies that significant and positive values of spatial lag coefficient indicate a positive spatial interaction between wards and variable like total coverage area;worker density have shown positive and significant effects on trips of public transportation.

关键词： GIs spatial analysis urban form public transportation

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A numerical technique based on collocation method for solving modified Kawahara equation

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Journal of Ocean Engineering and science 2018年第1期3卷 67-75页

作者： Turgut Ak s.Battal Gazi Karakoc Department of Transportation Engineering Yalova UniversityYalova77200 Turkey Department of Mathematics Faculty of Science and ArtNevsehir Haci Bektas Veli UniversityNevsehir50300 Turkey

In this article,a numerical solution of the modified Kawahara equation is presented by septic B-spline collocation *** the von-Neumann stability analysis,the present method is shown to be unconditionally stable.L 2 and L∞error norms and conserved quantities are given at selected *** accuracy of the proposed method is checked by test problems including motion of the single solitary wave,interaction of solitary waves and evolution of solitons.

关键词： Modified Kawahara equation Finite element method Collocation solitary waves B-spline

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Empirical analysis for the characterization of geo-mechanical strength and pressure regime:Implications on hydraulic fracturing stimulation

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Petroleum 2019年第3期5卷 260-270页

作者： Dorcas s.Eyinla Michael A.Oladunjoye Department of Earth sciences Adekunle Ajasin UniversityNigeria Department of Geology University of IbadanNigeria

Among the several activities involved in oil exploration are the determination of hydrocarbon in-place and mechanical competency of the oil *** pressure regimes of the formation have also become vital properties which must be well known to ensure preliminary awareness of the hydraulic *** study seeks to adopt a prediction strategy of the overall geo-mechanical competency and strength of the formation,using a less stressful computational process and an empirical analysis,developed using three wells from ED BON area in parts of Niger *** constants such as Poisson Ratio,Young's,shear and Bulk moduli which are the parameters for characterizing rock mechanical properties were estimated,as well as the subsurface formation pressures and the associated fracture gradient using P-wave sonic and density *** results from the analysis showed that there is correlation between elastic strength and fracture pressure.

关键词： Elastic strength Hydraulic fracturing Competency Prediction strategy Geomechanical parameters

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