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Spatial distribution of δ2H and δ18O values in the hydrologic cycle of the Nile basin

Journal of Arid Land 2015年第2期7卷 133-145页

作者： jeff b langman School of Science and Engineering American University in Cairo Department of Geological Sciences University of Idaho

Existing δ2H and δ18O values for precipitation and surface water in the Nile basin were used to analyze precipitation inputs and the influence of evaporation on the isotopic signal of the Nile River and its tributaries. The goal of the data analysis was to better understand basin processes that influence seasonal streamflow for the source waters of the Nile River, because climate and hydrologic models have continued to produce high uncertainty in the prediction of precipitation and streamflow in the Nile basin. An evaluation of differences in precipitation δ2H and δ18O values through linear regression and distribution analysis indicate variation by region and season in the isotopic signal of precipitation across the Nile basin. The White Nile basin receives precipitation with a more depleted isotopic signal compared to the blue Nile basin. The hot temperatures of the Sahelian spring produce a greater evaporation signal in the precipitation isotope distribution compared to precipitation in the Sahara/Mediterranean region, which can be influenced by storms moving in from the Mediterranean Sea. The larger evaporative effect is reversed for the two regions in summer because of the cooling of the Sahel from inflow of Indian Ocean monsoon moisture that predominantly influences the climate of the blue Nile basin. The regional precipitation isotopic signals convey to each region＇s streamflow, which is further modified by additional evaporation according to the local climate. Isotope ratios for White Nile streamflow are significantly altered by evaporation in the Sudd, but this isotopic signal is minimized for streamflow in the Nile River during the winter, spring and summer seasons because of the flow dominance of the blue Nile. During fall, the contribution from the White Nile may exceed that of the blue Nile, and the heavier isotopic signal of the White Nile becomes apparent. The variation in climatic conditions of the Nile River basin provides a means of identifying mech

关键词： Nile River arid environment deuterium excess regional climate model uncertainty evaporation isotope effects

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Seasonal changes in Hermit Thrush (Catharus guttatus) song syntax

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Avian Research 2024年第2期15卷 172-179页

作者： Sean P.Roach Luke C.McLean jeff W.MacLeod Leslie S.Phillmore Psychology Department University of New Brunswick Saint John100 Tucker Park RoadSaint JohnNBCanada Department of Psychology and Neuroscience Dalhousie University1355 Oxford StHalifaxNSB3H 4J1Canada

In many songbird species,birdsong features phonological syntax,meaning that the units within their vocal se-quences are ordered in a non-random way that adheres to a *** such syntactical patterns have been richly described in many species,comparatively little is known about how those patterns contribute to song achieving its important *** each of song’s main functions,territorial defense and mate attraction,evidence of a role for syntax is *** species for which syntax has been thoroughly described is the Hermit Thrush(Catharus guttatus),which presents song types from their repertoires in a semi-predictable order and,in doing so,rapidly cycle up and down the frequency *** objective of the present study was to explore the importance of song syntax in the Hermit Thrush through a within-subject examination of how measures of syntax,such as the predictability of song type order within song sequences,shift over the breeding *** hypothesized that,if such syntactical characteristics are important to breeding behaviour,they would be most prominent at the start of the breeding season when activity associated with territory establishment and mate attraction is most *** revealed that,as predicted,the rigidness of song type ordering within se-quences was highest at the start of the season and declined *** song type sequences were most predictable at the vitally important early part of the breeding season fit our hypothesis that this aspect of song syntax is important to song’s functions related to territory establishment and/or mate *** work will clarify whether that role relates to one of song’s two main functions or serves song transmission in some broader way.

关键词： birdsong Hermit Thrush Seasonal change Stereotypy Syntax

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A comparative study on the reactivity of charged Ni-rich and Ni-poor positive electrodes with electrolyte at elevated temperatures using accelerating rate calorimetry

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Journal of Energy Chemistry 2021年第9期30卷 523-530页

作者： Dongxu Ouyang Yulong Liu Ines Hamam Jian Wang jeff Dahn State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026AnhuiChina Department of Physics and Atmospheric Science Dalhousie UniversityHalifax B3H4R2Canada Department of Process Engineering and Applied Science Dalhousie UniversityHalifax B3H3J5Canada

The reactivity between charged Li(Li_(0.115)Mn_(0.529)Ni_(0.339)Al_(0.017))O_(2)(Li-rich),single crystal Li(Ni_(0.8)Mn_(0.1)Co_(0.1))O_(2)(SC-NMC811),LiFePO_(4)(LFP) and LiMn_(0.8)Fe_(0.2)PO_(4)(LMFP) positive electrodes at different states of charge(SOCs) and traditional carbonate-based electrolyte at elevated temperatures is systematically studied using accelerating rate calorimetry(ARC).The results show that the SOC greatly affects the thermal stability of the Li-rich and SC-NMC811 when traditional carbonate-based electrolyte is *** an increase in the SOC increases the energy density of lithium-ion cells,it also increases the reactivity between charged Li-rich and SC-NMC811 samples with electrolyte at elevated *** comparison with SC-NMC811,the Li-rich samples are much more stable at elevated temperatures,and the latter have higher specific ***-NMC811 samples are less reactive than traditional polycrystalline *** LFP and LMFP samples show excellent thermal stability at elevated *** substitution of Fe by Mn in the olivine series positive materials does not impact the reactivity with electrolyte.

关键词： Lithium-ion cells Accelerating rate calorimetry Positive electrodes Safety

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bending energy of a vesicle to which a small spherical particle adhere:An analytical study

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Chinese Physics b 2015年第9期24卷 572-580页

作者：曹思勤韦广红 jeff Z.Y.Chen State Key Laboratory of Surface Physics Key Laboratory for Computational Physical Sciences (Ministry of Education)Department of PhysicsFudan University Department of Physics and Astronomy University of Waterloo

On the basis of Helfrich＇s bending energy model, we show that the adsorption process of a small spherical particle to a closed vesicle can be analytically studied by retaining the leading terms in an expansion of the shape equation. Our general derivation predicts the optimal binding sites on a vesicle, where the local membrane shape of the binding site could be non-axisymmetric before the continuous adhesion transition takes place. Our derivation avoids directly solving the shape equation and depends on an integration of the contact-line condition. The results are verified by several examples of independent numerical solutions.

关键词： membrane conformation Helfrich model nano-particle adsorption phase transition

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bioreductive prodrugs as cancer therapeutics:targeting tumor hypoxia

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Chinese Journal of Cancer 2014年第2期33卷 80-86页

作者： Christopher P.Guise Alexandra M.Mowday Amir Ashoorzadeh Ran Yuan Wan-Hua Lin Dong-Hai Wu jeff b.Smaill Adam V.Patterson Ke Ding Auckland Cancer Society Research Centre School of Medical Sciences The University of Auckland The Key Laboratory of Regenerative biology Guangzhou Institute of Biomedicine and Health Chinese Academy of Sciences

Hypoxia, a state of low oxygen, is a common feature of solid tumors and is associated with disease progression as well as resistance to radiotherapy and certain chemotherapeutic drugs. Hypoxic regions in tumors, therefore, represent attractive targets for cancer therapy. To date, five distinct classes of bioreactive prodrugs have been developed to target hypoxic cells in solid tumors. These hypoxia-activated prodrugs, including nitro compounds, N-oxides, quinones, and metal complexes, generally share a common mechanism of activation whereby they are reduced by intracellular oxidoreductases in an oxygensensitive manner to form cytotoxins. Several examples including PR-104, TH-302, and EO9 are currently undergoing phase II and phase III clinical evaluation. In this review, we discuss the nature of tumor hypoxia as a therapeutic target, focusing on the development of bioreductive prodrugs. We also describe the current knowledge of how each prodrug class is activated and detail the clinical progress of leading examples.

关键词：癌症治疗生物还原缺氧肿瘤前体药物药物前体细胞毒素硝基化合物

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Concept development and testing of the UK’s first hydrogenhybrid train(HydroFLEX)

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Railway Engineering Science 2021年第3期29卷 248-257页

作者： Charles Calvert jeff Allan Peter Amor Stuart Hillmansen Clive Roberts Paul Weston birmingham Centre for Railway Research and Education School of EngineeringUniversity of BirminghamEdgbastonBirmingham B152TTUK jeff Vehicles Ltd BeavercreekUSA

In October 2018,Porterbrook and the University of birmingham announced the HydroFLEX project,to demonstrate a hydrogen-hybrid modified train atRail Live *** concept of modifying a Class 319 Electric Multiple Unit was developed,with equipment including a fuel cell stack,traction battery,24 V control system and hydrogen storage elements to be mounted inside one of the *** was followed by procurement of a fuel cell stack,traction batteries,and control equipment,which was then installed inside the train,being fixed to the seat *** substantial change from the concept was the provision of considerably more hydrogen storage than the minimum necessary,providing the train with more potential to be further modified to allow for higher speed mainline *** the Rail Live exhibition where HydroFLEX was demonstrated,numerous modifications were performed to increase the reliability and power of the HydroFLEX train,primarily concerned with modifying the base train logic,with the aim of a successfulmainline *** this effort was a multitude of documentation concerning safety,operations,and approvals to gain approvals from the relevant approvals *** project demonstrated the feasibility of using hydrogen fuel cells as an autonomous fuel for railway propulsion systems,which has the potential for full decarbonisation.

关键词： Hydrogen Fuel cell Hybrid Systems engineering

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Development and optimization of thermal contrast amplification lateral flow immunoassays for ultrasensitive HIV p24 protein detection

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Microsystems & Nanoengineering 2020年第1期6卷 683-693页

作者： Li Zhan Timothy Granade Yilin Liu Xierong Wei Ae Youngpairoj Vickie Sullivan jeff Johnson John bischof Department of Mechanical Engineering University of MinnesotaMinneapolisMNUSA Centers for Disease Control and Prevention AtlantaGAUSA Department of biomedical Engineering University of MinnesotaMinneapolisMNUSA

Detection of human immunodeficiency virus(HIV)p24 protein at a single pg/ml concentration in point-of-care(POC)settings is important because it can facilitate acute HIV infection diagnosis with a detection sensitivity approaching that of laboratory-based ***,the limit of detection(LOD)of lateral flow immunoassays(LFAs),the most prominent POC diagnostic platform,falls short of that of laboratory protein detection methods such as enzyme-linked immunosorbent assay(ELISA).Here,we report the development and optimization of a thermal contrast amplification(TCA)LFA that will allow ultrasensitive detection of 8 pg/ml p24 protein spiked into human serum at POC,approaching the LOD of a laboratory *** achieve this aim,we pursued several innovations as follows:(a)defining a new quantitative figure of merit for LFA design based on the specific to nonspecific binding ratio(bR);(b)using different sizes and shapes of gold nanoparticles(GNPs)in the systematic optimization of TCA LFA designs;and(c)exploring new laser wavelengths and power regimes for TCA LFA ***,we optimized the blocking buffer for the membrane and running buffer by quantitatively measuring the bR using a TCA *** TCA reader interprets the thermal signal(i.e.,temperature)of GNPs within the membrane when irradiated by a laser at the plasmon resonance wavelength of the *** process results in higher detection and quantitation of GNPs than in traditional visual detection(i.e.,color intensity).Further,we investigated the effect of laser power(30,100,200 mW),GNP size and shape(30 and 100 nm gold spheres,150 nm gold-silica shells),and laser wavelength(532,800 nm).Applying these innovations to a new TCA LFA design,we demonstrated that 100nm spheres with a 100 mW 532 nm laser provided the best performance(i.e.,LOD=8pg/ml).This LOD is significantly better than that of the current colorimetric LFA and is in the range of the laboratory-based p24 *** summary,this TCA LFA for p24 prote

关键词： optimization approaching flow

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Is pork trade good for China's greenhouse gas emissions?

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Chinese Journal of Population,Resources and Environment 2017年第4期15卷 301-311页

作者： Hongjun Tao jeff Luckstead Liang Zhao Christopher G Davis School of Economics and Management Fuzhou University Division of Agriculture and bumpers College University of Arkansas School of Economics Fujian Normal University Markets and Trade Economics Division Economic Research Service U.S.Department of Agriculture

China produces the largest amount of pork in the world, which emits the largest amount of greenhouse gases （GHGs）. This paper calculates GHG emissions from China＇s hog production at the provincial level using newly published emission factors~ Empirical results show that GHG emissions from China＇s hog production mainly respond to the scale intensity~ Capital abundance and income contribute positively to GI-IG emissions from hog production. Pork trade increases GHG emissions from China＇s hog produc- tion with a significantly direct effect, reduces GHG emissions through indirect technique effects.

关键词： China's pork trade greenhouse gas emissions scale composition andtechnique effect free trade

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机器人定位精度及标定非概率可靠性方法研究

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仪器仪表学报 2018年第12期39卷 109-120页

作者：孙剑萍 jeff Xi 汤兆平华东交通大学交通运输与物流学院南昌330013 瑞尔森大学工程与建筑科学学院多伦多M5B 2K3

机器人工作中往往存在着大量不确定性,从而导致其精确标定的复杂化。综合考虑机器人各连杆参数的不确定性区间取值对末端精度的影响,研究定位精度的可靠性及标定问题。基于区间数学,提出了一种基于非概率模型的机器人定位精度及参数标... 详细信息

机器人工作中往往存在着大量不确定性,从而导致其精确标定的复杂化。综合考虑机器人各连杆参数的不确定性区间取值对末端精度的影响,研究定位精度的可靠性及标定问题。基于区间数学,提出了一种基于非概率模型的机器人定位精度及参数标定的可靠性度量及分析方法,以REIS RV 16型机器人为例,求解了定位误差以及运动参数偏差的取值区间,分析了基于区间算法的机器人定位精度及标定非概率可靠性。所提方法可以在制造或装配阶段,对机器人末端的空间位置范围进行预测,以及对运动学参数的取值范围进行估计,方便后期对定位点的理论坐标进行逆补偿,保证机器人定位与标定的有效性和可靠性。

关键词：机器人标定定位精度非概率可靠性区间分析

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近似度加权平均插值的机器人精度补偿方法研究

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仪器仪表学报 2019年第11期40卷 128-137页

作者：孙剑萍 jeff Xi 汤兆平华东交通大学交通运输与物流学院南昌330013 瑞尔森大学工程与建筑科学学院多伦多M5B 2K3

针对机器人标定高度依赖于构型的问题,考虑到机器人末端不同位置矢量间的距离、夹角以及在空间上形成的三角形面积对矢量近似度的关联,引入机器人位姿及位姿误差矢量近似度的概念及度量方法,制定基于近似度的判别规则及使用条件,对目标... 详细信息

针对机器人标定高度依赖于构型的问题,考虑到机器人末端不同位置矢量间的距离、夹角以及在空间上形成的三角形面积对矢量近似度的关联,引入机器人位姿及位姿误差矢量近似度的概念及度量方法,制定基于近似度的判别规则及使用条件,对目标位姿邻域内的数据库样本进行筛选。在此基础上,提出一种基于近似度加权平均插值的机器人精度补偿方法,利用工作空间中筛选出的采样点位姿及误差数据,对目标点的位姿误差进行插值预测。实例结果表明,该方法能有效提高机器人位姿误差补偿的空间适应性,满足高端领域要求。

关键词：机器人定位精度补偿近似度插值法

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