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Decreasing nutrient concentrations in soils and trees with increasing elevation across a treelineecotone in Rolwaling Himal, Nepal

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Journal of Mountain Science 2017年第5期14卷 843-858页

作者： Simon DROLLINgER michael MULLER Timo KOBL Niels SCHWAB Jurgen BOHNER udo SCHICKHOFF Thomas SCHOLTEN geoecology Department of Geography and Regional Research University of Vienna Vienna Austria Soil Science and geomorphology Department of Geosciences Uniuersity of Tubingen Tubingen Germany CEN Center for Earth System Research and Sustainability Institute of Geography University of Hamburg Hamburg Germany

At a global scale, tree growth in alpine treeline ecotones is limited by low temperatures. At a local scale, however, tree growth at its upper limit depends on multiple interactions of influencing factors and mechanisms. The aim of our research was to understand local scale effects of soil properties and nutrient cycling on tree growth limitation, and their interactions with other abiotic and biotic factors in a near-natural Himalayan treeline ecotone. Soil samples of different soil horizons, litter, decomposition layers, and foliage samples of standing biomass were collected in four altitudinal zones along three slopes, and were analysed for exchangeable cations and nutrient concentrations, respectively. Additionally, soil and air temperature, soil moisture, precipitation, and tree physiognomy patterns were evaluated. Both soil nutrients and foliar macronutrient concentrations of nitrogen(N), magnesium(Mg), potassium(K), and foliar phosphorus(P) decrease significantly with elevation. Foliar manganese(Mn) concentrations, bycontrast, are extraordinarily high at high elevation sites. Potential constraining factors on tree growth were identified using multivariate statistical approaches. We propose that tree growth, treeline position and vegetation composition are affected by nutrient limitation, which in turn, is governed by low soil temperatures and influenced by soil moisture conditions.

关键词： Foliar nutrients Himalaya Nitrogen Nutrient cycling Podzol Treeline

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Separating polydisperse particles using electrostatic precipitators with wire and spiked-wire discharge electrode design

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Particuology 2018年第3期16卷 10-17页

作者： Soren Sander Steffen gawor udo Fritsching Process Engineering Stiftung Institut ffir Werlcstofftechnik Badgasteiner Strasse 3 28359 Bremen Germany Particles and Process Engineering University of Bremen Bibliothekstrasse 1 28359 Bremen. Germany

Numerical simulations of electrostatic precipitators featuring wire and spiked electrode designs were performed to determine particle behavior and separation efficiency. The applied-voltage mechanism that alters the flow structure of particles through ionic winds and mean electric fields are revealed. Numeri- cal studies throughout the past years have shown these structures for channel and pipe configurations. However, less attention was given to field averaging for the ni,~r-product and electric field. Our study focuses on this averaging and illustrates relevant differences between multidimensional setups concern- ~ng these fields. Turbulence was modeled using the Reynolds-averaged Navier-Stokes equations with a second-order Reynolds-stress-model closure. A high three-dimensionality of the ionic wind-induced turbulence is presented. This leads to an increase in the submicron-particle precipitation rate. The results confirm the dependence of separation efficiency on particle density and permittivity, thereby showing the advantages of spiked wires compared with wire-plate setups used in electrostatic precipitators.

关键词： Electro-hydrodynamic CFD simulation Electrostatic particle precipitation Electrode design Collection efficiency

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Implications of tree species–environment relationships for the responsiveness of Himalayan krummholz treelines to climate change

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Journal of Mountain Science 2017年第3期14卷 453-473页

作者： Niels SCHWAB udo SCHICKHOFF Birgit BURZLE michael MULLER Jurgen BOHNER Ram Prasad CHAUDHARY Thomas SCHOLTEN Jens OLDELAND CEN Center for Earth System Research and Sustainability Institute of GeographyUniversity of HamburgBundesstrafle 5520146 HamburgGermany Department of geosciences Chair of Soil Science and CeomorphologyUniversity of TübingenGermany Research Centre for Applied Science and Technology&Central Department of Botany Tribhuvan UniversityNepal Biocentre Klein Flottbek University of HamburgOhnhorststr.1822609 HamburgGermany

Climate warming is expected to advance treelines to higher elevations. However, empirical studies in diverse mountain ranges give evidence of both advancing alpine treelines as well as rather insignificant responses. In this context, we aim at investigating the sensitivity and responsiveness of the near-natural treeline ecotone in Rolwaling Himal, Nepal, to climate warming. We analysed population densities of tree species along the treeline ecotone from closed forest stands via the krummholz belt to alpine dwarf shrub heaths （3700-4200 m） at 50 plots in 2013 and 2014. We quantified species - environment relationships, i.e. the change of environmental conditions （e.g., nutrient and thermal deficits, plant interactions） across the ecotone by means of redundancy analyses, variation partitioning and distance-based Moran＇s eigenvector maps. In particular, we focus on explaining the high competitiveness of Rhododendron campanulatum forming a dense krummholz belt and on the implications for the responsiveness of Himalayan krummholz treelines to climate change. Results indicate that treeline trees in the ecotone show species-specific responses to the influence of environmental parameters, and that juvenile and adult tree responses are modulated by environmental constraints in differing intensity. Moreover, the species - environment relationships suggest that the investigated krummholz belt will largely prevent the upward migration of other tree constrain the future response species and thus of Himalayan krummholz treelines to climate warming.

关键词： Himalaya Nepal Population structure Rhododendron campanulatum Spatial patterns Species-environment relationships Stand density Variation partitioning

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Comparison of antioxidant activity of insulin, Ocimum gratissimum L., and Vernonia amygdalina L. in type 1 diabetic rat model

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Journal of Integrative Medicine 2017年第4期15卷 302-309页

作者： Uduak Akpan Okon Idorenyin udo Umoren Department of Physiology Faculty of Basic Medical Sciences College of Health Sciences University of Uyo

OBJECTIVE： Diabetes mellitus （DM） is known to be associated with increase of oxidative stress products. The direction of effect of any treatment on these products could therefore be a reliable measure of its efficacy on DM. So the aim of this study was to investigate the activity of insulin, Ocimum gratissimum L. （Og） and Vernonia amygdafina L. （VA） on oxidative stress ***： Thirty-six female Wistar rats weighing 150-200 g were randomly divided into six groups of six rats each. Thirty rats were induced for type 1 DM （DM1） with a single intraperitoneal administration of 65 mg/ kg body weight of streptozotocin. group 1 was normal control and was administered distilled water while group 2 served as DM1 control group; groups 3, 4, 5 and 6 were diabetic rats treated with 208 mg/kg Og （DM1 ＋ Og）, 52 mg/kg VA （DM1 ＋ VA）, 208 mg/kg Og ＋ 52 mg/kg VA （DMI＋Og ＋VA） and 0.16 IU insulin （DM1 ＋ insulin） respectively. Determination of methemoglobin and sulfhemoglobin was achieved by the absorption spectrum principle. Red blood cell （RBC） catalase was assayed by continuous spectrophotometric ***： The RBC catalase concentration was significantly decreased in the DM1 and DMI＋VA groups when compared with the normal control. DM1 ＋ Og significantly increased RBC-catalase when compared to DMI. The methemoglobin concentration was significantly reduced in the DM1, DM1 ＋ VA, DM1 ＋ Og ＋ VA and DM1 ＋ insulin groups when compared to the normal control group. The sulfhemoglobin concentration was significantly increased in the diabetic control and the diabetic treated groups when compared to the normal control. DM1 ＋ Og reduced the sulfhemoglobin concentration when compared to DM1. The blood glucose concentration of all the diabetic groups was significantly raised compared to normal control. Og, VA and insulin significantly reduced the blood glucose concentration with the efficacy of Og and VA higher than ***： Adverse alteration of oxidative indices were obse

关键词： oxidative stress diabetes mellitus, type 1" insulin Ocimum gratissimum L. Vemonia amygdalina L.

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Nanotribological studies using nanoparticle manipulation: Principles and application to structural lubricity

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Friction 2014年第2期2卷 114-139页

作者： Dirk DIETZEL udo DSCHWARZ AndréSCHIRMEISEN Institute of Applied Physics(IAP) Justus-Liebig-Universität GiessenGermany Departments of Mechanical Engineering&Materials Science and Chemical&Environmental Engineering and Center for Research on Structures and Phenomena(CRISP) Yale UniversityNew HavenCTUSA

The term“structural lubricity”denotes a fundamental concept where the friction between two atomically flat surfaces is reduced due to lattice mismatch at the *** favorable circumstances,its effect may cause a contact to experience ultra-low friction,which is why it is also referred to as“superlubricity”.While the basic principle is intriguingly simple,the experimental analysis of structural lubricity has been *** of the main reasons for this predicament is that the tool most frequently used in nanotribology,the friction force microscope,is not well suited to analyse the friction of extended *** overcome this deficiency,substantial efforts have been directed in recent years towards establishing nanoparticle manipulation techniques,where the friction of nanoparticles sliding on a substrate is measured,as an alternative approach to nanotribological *** choosing appropriate nanoparticles and substrates,interfaces exhibiting the characteristics needed for the occurrence of structural lubricity can be *** a consequence,nanoparticle manipulation experiments such as in this review represent a unique opportunity to study the physical conditions and processes necessary to establish structural lubricity,thereby opening a path to exploit this effect in technological applications.

关键词： Nanotribology nanoparticle manipulation friction force microscopy structural lubricity superlubricity HOPg

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Particle penetration in fiber filters

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Particuology 2018年第5期16卷 70-79页

作者： Norbert Riefler Martina Ulrich Marko Morshaiuser udo Fritsching Process Engineering Institute of Materials ScienceBadgasteiner Strasse 328359BremenGermany Lydall gutsche gmbH & Co.Kg Hermann-Muth-Str.836039FuldaGermany Particles and Process Engineering University of BremenBibliothekstrasse 128359BremenGermany

Particle separation from gases is an important unit operation in manifold industrial applications,such as those conducted in environmental *** analysis of particle penetration and separation in fiber filters,standard dust particles (Al2O3)were loaded in the gas flow of a filter test facility and deposited within new and uncharged fiber *** loaded filters were analyzed by micro-computer tomography and scanning electron ***-dimensional tomograms of the samples show an exponential decay of the penetration depth of the *** dependency is confirmed by simulations conducted using the discrete element method coupled with computational fluid dynamics within unloaded and loaded fiber *** processes of particle separation at the fibers as well as the filtration efficiency and time-dependent filtering process are derived from the *** particle clustering in the filter medium and partial filter clogging are thus identified.

关键词： Particle filtration Fiber filter X-ray microtomography Computational fluid dynamics-discrete element method coupling High-fidelity simulation Transient mesh morphing

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How to Become a good Healer in Chinese Medicine?

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Chinese Medicine and Culture 2020年第1期3卷 44-46页

作者： udo Lorenzen guest Professor Chengdu University of Traditional Chinese MedicineChengduChina Director Ausbildungszentrum Nord für Klassische Akupunktur und TCMGermany

Today,traditional Chinese medicine(TCM)is a relatively new product of the People’s Republic of *** 1950 Chairman Mao aimed atthe standardization and simplification of many traditional medical schools to guarantee a stable health care for the *** academic exchange between east and west increased during the last 60 years,TCM appears today more and more as the“real”and“old”Chinese *** is that really the case?There is a famous saying in China:Medicine is also idea(医者意也Yi Zhe Yi Ye),so what are the ideas about a good healer?In my article I try to find it *** through the old classical books,there are some good ideas about a good healer,especially in the Ling Shu(《灵枢》Spiritual Pivot).The root of all is the spirit(神Shen).There are many other requirements to be a good healer,but without a stable Shen,no treatment can really touches the cause of the disease!

关键词： Acupuncture and moxibustion Chinese medicine healer

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Spatial and seasonal dynamics of soil loss ratio in mountain rangelands of south-western Kyrgyzstan

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Journal of Mountain Science 2016年第2期13卷 316-329页

作者： Maksim KULIKOV udo SCHICKI-IOFF Peter BORCHARDT CEN Center for Earth System Research and Sustainability Institute of Geography University of Hamburg Germany

Vegetation cover is the main factor of soil loss *** C-factor of the RUSLE(Revised Universal Soil Loss Equation) was predicted with NDVI,ground data and exponential regression equation for mountain rangelands of *** series of C-factor,precipitation and temperature were decomposed into seasonal and trend components with STL(seasonal decomposition by loess) to assess their interrelations.C-factor,precipitation and temperature trend components indicated significant lagged correlation,whereas seasonal components indicated more complex relations with climate factors which can be promoting as well as limiting factors for vegetation development,depending on the *** springs and hot summers may increase soil loss dramatically,whereas warm and dry springs with rainy summers can decrease *** slopes indicated higher soil loss ratio,whereas flat areas were better protected by vegetation.

关键词： Soil loss ratio C-factor RUSLE NDVI Time series Remote sensing

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Ferromagnetism and ferroelectricity in a superlattice of antiferromagnetic perovskite oxides without ferroelectric polarization

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npj Computational Materials 2023年第1期9卷 632-637页

作者： Paresh C.Rout Avijeet Ray udo Schwingenschlögl Physical Sciences and Engineering Division(PSE) King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

We study the structural,electronic,and magnetic properties of the SrCrO_(3)/YCrO_(3) superlattice and their dependence on epitaxial *** discover that the superlattice adopts A-type antiferromagnetic(A-AFM)ordering in contrast to its constituents(SrCrO_(3):C-AFM;YCrO_(3):g-AFM)and retains it under compressive strain while becoming ferromagnetic(5μB per formula unit)at+1%*** obtained ferroelectric polarization is significantly higher than that of the R2NiMnO6/La2NiMnO6(R=Ce to Er)series of superlattices[***.5,4021(2014)]due to a large difference between the antipolar displacements of the Sr and Y *** superlattice is a hybrid-improper multiferroic material with a spontaneous ferroelectric polarization(13.5μC/cm^(2))approaching that of bulk BaTiO_(3)(19μC/cm^(2)).The combination of ferromagnetism with ferroelectricity enables multistate memory *** addition,the charge-order-driven p-type semiconducting state of the ferromagnetic phase(despite the metallic nature of SrCrO_(3))is a rare property and interesting for *** Carlo simulations demonstrate a magnetic critical temperature of 90 K for the A-AFM phase without strain and of 115 K for the ferromagnetic phase at+5%strain,for example.

关键词： ferroelectric superlattice ferromagnetic

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Modelling soil erodibility in mountain rangelands of southern Kyrgyzstan

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Pedosphere 2020年第4期30卷 443-456页

作者： Maksim KULIKOV udo SCHICKHOFF Alexander gRONgROFT Peter BORCHARDT Centrum für Erdsystemforschung und Nachhaltigkeit(CEN) Center for Earth System Research and SustainabilityInstitute of GeographyUniversity of HamburgHamburg D-20146(Germany) Centrum für Erdsystemforschung und Nachhaltigkeit(CEN) Center for Earth System Research and SustainabilityInstitute of Soil ScienceUniversity of HamburgHamburg D-20146(Germany)

Soil erosion in mountain rangelands in Kyrgyzstan is an emerging problem due to vegetation loss caused by overgrazing. It is further exacerbated by mountain terrain and high precipitation values in Fergana range in the south of Kyrgyzstan. The main objective of this study was to map soil erodibility in the mountainous rangelands of Kyrgyzstan. The results of this effort are expected to contribute to the development of soil erodibility modelling approaches for mountainous areas. In this study, we mapped soil erodibility at two sites, both representing grazing rangelands in the mountains of Kyrgyzstan and having potentially different levels of grazing pressure. We collected a total of 232 soil samples evenly distributed in geographical space and feature space. Then we analyzed the samples in laboratory for grain size distribution and calculated soil erodibility values from these data using the Revised Universal Soil Loss Equation (RUSLE) K-factor formula. After that, we derived different terrain indices and ratios of frequency bands from ASTER gDEM and LANDSAT images to use as auxiliary data because they are among the main soil forming factors and widely used for prediction of various soil properties. Soil erodibility was significantly correlated with channel network base level (geographically extrapolated altitude of water channels), remotely sensed indices of short-wave infrared spectral bands, exposition, and slope degree. We applied multiple regression analysis to predict soil erodibility from spatially explicit terrain and remotely sensed indices. The final soil erodibility model was developed using the spatially explicit predictors and the regression equation and then improved by adding the residuals. The spatial resolution of the model was 30 m, and the estimated mean adjusted coefficient of determination was 0.47. The two sites indicated different estimated and predicted means of soil erodibility values (0.035 and 0.039) with a 0.05 significance level, which i

关键词： channel network base level K-factor LANDSAT RUSLE soil enhancement ratio soil mapping slope terrain

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