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Growth, physiological characteristics and ion distribution of NaCl stressed Alhagi sparsifolia seedlings

Chinese Science bulletin 2008年第S2期53卷 169-176页

作者： arndt S. K. School of Forest and Ecosystem Science the University of Melbourne Water Street Creswick Vic. 3363 Australia

Alhagi sparsifolia is a leguminous perennial desert species that is plays an important role in dune stabilization and revegetation of degraded desert ecosystems. We investigated the effects of three different levels of salinity (50, 150, 250 mmol/L NaCl) on the growth, shoot photosynthetic parameters and salt distribution amongst different plant organs in one-year-old A. sparsifolia seedlings in a pot experiment over a 50 d period. The minimum (predawn) and maximum (midday) water potentials of A. sparsifolia seedlings decreased with the increase of external NaCl concentrations as a consequence of the osmotic or water deficit effect of saline solutions outside the roots. Salinity also reduced gas exchange parameters in A. sparsifolia, with seedlings subjected to salinity having lower photosynthesis rates and reduced stomatal conductances compared to the control. The reductions in photosynthetic rates in high salinity treatments of the A. sparsifolia seedlings were mainly caused by stomatal limitation. Consequently plants growing at greater external NaCl concentrations had significantly lower biomass accumulation compared to the control grown at 50 mmol/L. However, plants exposed to higher salinity were able to maintain growth throughout the experiment but allocated a greater proportion of biomass belowground. Plants exposed to higher external salinity levels had increased concentrations of Na+ and Cl- ions in shoots and roots, suggesting that A. sparsifolia seedlings were utilizing Na+ and Cl- as osmolytes to increase the cellular osmolality and decrease their water potential. We observed the greatest NaCl concentrations in the plants treated with 150 mmol/L NaCl indicating that there may be a threshold level of NaCl that can be tolerated by the plants. In conclusion our results indicate that A. sparsifolia seedlings are moderately salt tolerant. Photosynthetic gas exchange parameters were reduced by greater external salinity but the seedlings maintained substantial

关键词： Taklamakan Desert NaCl salinity Alhagi sparsifolia growth physiological indexes

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SUPERCAVITY MOTION WITH INERTIAL FORCE IN THE VERTICAL PLANE

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Journal of Hydrodynamics 2012年第5期24卷 752-759页

作者： YU Kai-ping ZOU Wang arndt Roger ZHANG Guang School of Astronautics Harbin Institute of TechnologyHarbin 150001China Saint Anthony Falls Laboratory University of MinnesotaMinneapolisUSA

The curvilinear motion in a vertical plane is one of the most important features of the supercavitating vehicle. It is of great significance to study the controllability and the maneuverability of the supercavitating vehicle. Models are built for the effects of the angle of attack, the gravity and the inertial force in the curvilinear motion in the vertical p｜ane. Numerica~ simulations are carried out for the supercavity motion based on these models combined with the Logvinovich model. It is shown that the maximum deviation displacement in the outward normal direction of the trajectory with a constant curvature, which occurs in the tail of the supercavity, increases as the cavitation number or the curvature radius of the supercavity trajectory decreases under the condition that other model and flow parameters are kept constant. For a varied curvature, the supercavity shape changes evidently because of the change of the ambient pressure, but with the same trend as in constant curvature. The deviation displacement increases along the supercavity length gradually.

关键词： supercavity inertial force curvilinear motion curvature radius

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Influence of floodwater irrigation on vegetation composition and vegetation regeneration in a Taklimakan desert oasis

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Chinese Science bulletin 2008年第S2期53卷 156-163页

作者： arndt S. K. Department of Forest and Ecosystem Science The University of Melbourne 500 Yarra Boulevard Richmond Vic. 3121 Australia

Naturally occurring floods in the summer months are the main source of surface water application in the foreland of Qira oasis, which is characterized by a hyperarid climate and is located at the southern fringe of the Taklimakan Desert. We investigated the impact of repeated artificial flood irrigation on seedling recruitment and growth of Alhagi sparsifolia and Karelinia caspica plant communities which are part of the dominant vegetation in Qira oasis. Flood irrigation was applied three times during the growing season and we studied the effect of irrigation on species recruitment, vegetation growth, spe- cies composition, and changes in soil water and nutrient concentrations in the soil profile. Results show that (1) repeated flood irrigation had a positive effect on seedling recruitment of the two species, with vegetative recruitment via root tillers being more important than seed recruitment for both species. (2) Irrigation promoted the germination and establishment of herbaceous weed species, which in- creased species diversity as well as ground coverage. (3) Irrigation also increased soil water and soil nutrient concentrations in the upper soil layer and changed the soil nutrients in the vertical profile. Available N, P, K and the total P and K increased in the soil profile. Our study demonstrates that naturally occurring flood irrigation has significant ecological benefits and plays an important role in promoting the renewal of desert vegetation and a short-term increase of soil nutrients. Our study also highlights the potential negative consequences for vegetation composition and rejuvenation if naturally occurring floods in the study area are diminished by either the effects of climate change or human management.

关键词： floodwater irrigation Alhagi.sparsifolia Karelinia caspica species recruitment vegetation composition soil nutrients

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Modeling and Simulation of Supercavity with Inertial Force in the Horizontal Curvilinear Motion

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China Ocean Engineering 2014年第1期28卷 31-42页

作者：邹望于开平 R.E.A.arndt 张广 School of Astronautics Harbin Institute of Technology Saint Anthony Falls Laboratory University of Minnesota

To make a curvilinear motion in the horizontal plane is one of the most contents for realizing the maneuverability of the supercavitating vehicle. It is significant to achieve the controllability and maneuverability of the vehicle in three dimensions both theoretically and practically on research. Models of angle of attack, gravity and inertial force effects on the supercavity in the horizontal curvilinear motion are established, respectively. The supercavity is simulated based on these models in combination with Logvinovich model and the unsteady gas-leakage rate model at the given ventilation rate, and the effect of the inertial force on it is analyzed numerically. Results show that the maximum deviation of the center line of the cross section of supercavity towards the outward normal direction of its trajectory increases as the cavitation number or curvature radius decrease and always occur in the tail because of the increase of inertial effects along the axis of supercavity from the cavitator when other models and flow parameters are constant for the given trajectory curvature. For the variable curvature, the supercavity sheds due to its instability caused by the time-varying angle of attack. The deviation increases along the length of supercavity if the curvature remains the same sign.

关键词： supercavity inertial force curvilinear motion curvature rodius

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Supported ZnO catalysts for the conversion of alkanes:About the metamorphosis of a heterogeneous catalyst

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Journal of Natural Gas Chemistry 2012年第5期21卷 581-594页

作者： S.arndt b.Uysal A.berthold T.Otrebma Y.Aksu M.Driess R.Schomcker Technische Universitāt zu berlin Institut fūr ChemieStraβe des 17 Juni 12410623 BerlinGermany Akdeniz University Department of Chemistry07058 AntalyaTurkey Technische Universitāt zu berlin Institut fūr Werkstof fwissenschaftenHardenbergstr 4010623 BerlinGermany

ZnO could be a suitable catalyst for the oxidative conversion of CH4,C2H6 and ***,the main drawback is its thermal ***,ZnO supported on ZrO 2,TiO2,γ-Al2O and SiO2 was investigated for the oxidative dehydrogenation of propane and ethane,and the oxidative coupling of *** stability of the supported ZnO is partially improved,but ZnO reacts with the support material,forming new compounds （Zn-zirconates,-titanates,-aluminates and-silicates）,which already occurs below reaction *** might also be the case for many other heterogeneous catalysts.

关键词： oxidative dehydrogenation oxidative coupling of methane oxidative dehydrogenation of ethane oxidative dehydrogenation of propane ZnO

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Cinema 4d 10 workshop 1

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2007年

作者： arndt von Koenigsmarck

ISBN: (纸本)9780240808970

Model, animate and render with a practical command of all the essential functions and tools in CINEMA 4D 10. Detailed tutorials, suitable for novices and experienced users alike, demonstrate how to navigate the redesigned UI and orient you to the workflow. Next, the author guides you through the creation of a more complex project in which you model, create, apply textures, light, and render a final showcase image of a sports car. Finally, you will model, texture and prepare a comic character for animation using the new powerslider, timeline and the revised MOCCA *** on your command of the essentials with an introduction to the new layer system as well as these advanced skills:* Light, texture, and shade with CINEMA's material system, bodyPaint 3D, and the integrated shaders* build complex mechanical and organic models using NURbS and polygon tools* Compose 3D content into photos* Render with advanced techniques such as Multi Pass rendering, HDRI lighting and radiosity* Simplify animation setups using XPresso constrains* Work with specialized tools such as HAIR, Clothilde or SKY for special effectsThe companion CD includes all of the required tutorial media, a bonus chapter on character modeling, Macintosh and PC demo versions of CINEMA 4D 10, and a limited edition of the PhotoMatch plug-in that permits you to easily insert 3D objects into photos.

关键词： Cinema 4D XL.Computer animation.Threedimensional display systems.Computer graphics.

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Latent HIV-1 TAR Regulates 7SK-responsive P-TEFb Target Genes and Targets Cellular Immune Responses in the Absence of Tat

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Genomics, Proteomics & bioinformatics 2017年第5期15卷 313-323页

作者： Sebastian Eilebrecht bernd-Joachim benecke arndt G. benecke CNRS UMR8246 Université Pierre et Marie Curie Paris 75005 France ACSIOMA GmbH Technologiezentrum Ruhr Bochum 44799 Germany Center for Innate Immunity and Immune Disease University of Washington School of Medicine Seattle WA 98195 USA

The transactivating response element （TAR） structure of the nascent HIV-1 transcript is critically involved in the recruitment of inactive positive transcription elongation factor b （P-TEFb） to the promoter proximal paused RNA polymerase II. The viral transactivator Tat is responsible for subsequent P-TEFb activation in order to start efficient viral transcription elongation. In the absence of the viral transactivator of transcription （Tat）, e.g., during latency or in early stages of HIV tran- scription, TAR mediates an interaction of P-TEFb with its inhibitor hexamethylene bis-aeetamide- inducible protein 1 （HEXIM1）, keeping P-TEFb in its inactive form. In this study, we address the function of HIV-1 TAR in the absence of Tat by analyzing consequences of HIV-1 TAR overexpres- sion on host cellular gene expression. An RNA chimera consisting of Epstein-barr virus-expressed RNA 2 （EbER2） and HIV-1 TAR was developed to assure robust overexpression of TAR in HEK293 cells. The overexpression results in differential expression of more than 800 human genes. A significant proportion of these genes is involved in the suppression of cellular immune responses, including a significant set of 7SK-responsive P-TEFb target genes. Our findings identify a novel role for HIV-1 TAR in the absence of Tat, involving the interference with host cellular immune responses by targeting 7SK RNA-mediated gene expression and P-TEFb inactivation.

关键词： HIV-1 Latency TAR 7SK RNA Cellular immunity

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Global Value Chains, Horizontal Intra-lndustry Trade and the Heterogeneous Firm

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2018年第1期13卷 68-82页

作者： Sven W. arndt Robert Day School of Economics and Finance Claremont McKenna College Claremont CA91711 USA

This paper examines global value chains at the level of the heterogeneous firm. The context is a world of horizontal intra-industry trade, characterized by imperfect competition and product differentiation at the firm level. Standard microeconomic tools are employed to assess the effects of inter-firm dissimilarities in both demand and supply on firms＇ responses to changes in trade policy. In this set-up, dissimilarities in firm characteristics play roles similar to factor endowments and technology differences in traditional trade models. When cross-border production sharing （＂fragmentation＂） is introduced into this framework, those differences in firm characteristics determine the degree to which individual firms will enter into production networks. In this context, horizontal and vertical intra-industry tradel elements interact in their effects on firm decisions. Traditional comparative advantage considerations still govern the choice of off-shored activities, while direct competition between imports and exports expands the range of possible outcomes. Finally, it is shown that cross-border production sharing reduces the sensitivity of firms to variations in exchange rates, matching a phenomenon that has been observed in traditional country-level models.

关键词： heterogeneous firms global value chains intra-industry trade,intra-product specialization exchange-rate elasticities

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Normalization Using Weighted Negative Second Order Exponential Error Functions(NeONORM) Provides Robustness Against Asym-metries in Comparative Transcriptome Profiles and Avoids False Calls

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Genomics, Proteomics & bioinformatics 2006年第2期4卷 90-109页

作者： Sebastian Noth Guillaume brysbaert arndt benecke Systems Epigenomics Group Institut des Hautes Etudes Scientifiques/Institut de Recherches InterdisciplinairesCNRS/INSERM 91440 Bures sur Yvette France.

Studies on high-throughput global gene expression using microarray technology have generated ever larger amounts of systematic transcriptome data. A major challenge in exploiting these heterogeneous datasets is how to normalize the expression profiles by inter-assay methods. Different non-linear and linear normalization methods have been developed, which essentially rely on the hypothesis that the true or perceived logarithmic fold-change distributions between two different assays are symmetric in nature. However, asymmetric gene expression changes are frequently observed, leading to suboptimal normalization results and in consequence potentially to thousands of false calls. Therefore, we have specifically investigated asymmetric comparative transcriptome profiles and developed the normalization using weighted negative second order exponential error functions （NeONORM） for robust and global inter-assay normalization. NeONORM efficiently damps true gene regulatory events in order to minimize their misleading impact on the norrealization process. We evaluated NeONORM＇s applicability using artificial and true experimental datasets, both of which demonstrated that NeONORM could be systematically applied to inter-assay and inter-condition comparisons.

关键词： microarray statistical analysis normalization asymmetry robustness

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Generation of Synthetic Transcriptome Data with Defined Statistical Properties for the Development and Testing of New Analysis Methods

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Genomics, Proteomics & bioinformatics 2007年第1期5卷 45-52页

作者： Guillaume brysbaert Sebastian Noth arndt benecke Systems Epigenomics Group Institut des Hautes Etudes Scientifiques/Institut de Recherches InterdisciplinairesCNRS/INSERM 91440 Bures sur Yvette France

We have previously developed a combined signal/variance distribution model that accounts for the particular statistical properties of datasets generated on the Applied biosystems Ab1700 transcriptome system. Here we show that this model can be efficiently used to generate synthetic datasets with statistical properties virtually identical to those of the actual data by aid of the JAVA application *** creator 1.0 that we have developed. The fundamentally different structure of Ab1700 transcriptome profiles requires re-evaluation, adaptation, or even redevelopment of many of the standard microarray analysis methods in order to avoid misinterpretation of the data on the one hand, and to draw full benefit from their increased specificity and sensitivity on the other hand. Our composite data model and the *** creator 1.0 application thereby not only present proof of the correctness of our parameter estimation, but also provide a tool for the generation of synthetic test data that will be useful for further development and testing of analysis methods.

关键词： transcriptome microarray analysis signal/variance distribution distribution modeling parameter approximation synthetic data generation

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