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How do altitude and soil properties influence the taxonomic and phylogenetic structure and diversity of Brazilian páramo vegetation?

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Journal of Mountain Science 2020年第5期17卷 1045-1057页

作者： Markus GASTAUER Jan THIELE stefan POREMBSKI Andreza Viana NERI Instituto Tecnologico Vale R.Boaventura da Silva955CEP 66055-090Bairro NazareBelemPABrazil Universidade Federal do Para Programa de pos-graduacao em EcologiaRuaAugusto Correa01CEP 66075-110GuamaBelemBrazil Thünen Institute Institute of BiodiversityBundesallee 6538116 BraunschweigGermany University of Rostock Institute of BioscienceDepartment of Botany and Botanical GardenWismarsche Str.44/45D-18051 RostockGermany Universidade Federal de Vicosa Department of Plant BiologyLaboratory of Ecology and Evolution of PlantsCampus Universitario s/n36570-900VigosaMinas GeraisBrazil

Altitude and environmental variables such as edaphic properties are considered determinants of species distribution and community composition in mountain ***,we aimed to outline the effects of distinct mountain peaks,altitude and soil properties on community composition,species density,phylogenetic structure and diversity of angiosperm páramo communities from the Serra do Brigadeiro State Park,Minas Gerais,southeastern *** that,we identified all angiosperm species found in 300 plots(1 m×1 m)from three mountain peaks,measured soil depth and analyzed soil fertility and texture in each *** reduce the number of soil variables and species composition,we computed principal coordinates based on soil properties and principal coordinates based on species-plot matrix for each ***,we computed the standard effect sizes of the mean phylogenetic pairwise distance and the mean nearest phylogenetic taxon distance for each plot to investigate differences in the degree of relatedness among coexisting *** compared differences in response variables between peaks and modelled them in function of altitude and principle components of soil properties using mixed effect *** density and phylogenetic diversity differed between peaks,but,contrary to the previous findings,no relationships between species richness or phylogenetic diversity and altitude or soil properties were found,indicating that further investigations are necessary to understand the altitude-biodiversity relationship in Brazilian páramo *** composition differed between peaks and depended on altitude,soil properties and interactions between them,indicating that upward shifting of bioclimatic conditions due to climate changes may alter communities of this *** structure differed between peaks and was influenced by altitude and soil *** phylogenetic clustering increased with altitude,eventual upward movements of species in Brazilian

关键词： Mountainous ecosystems Altitudebiodiversity relationship High altitude grasslands Phylogenetic diversity Community assemblage Conservation

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High resolution, binder-free investigation of the intrinsic activity of immobilized NiFe LDH nanoparticles on etched carbon nanoelectrodes

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Nano Research 2018年第11期11卷 6034-6044页

作者： Patrick Wilde stefan Barwe Corina Andronescu Wolfgang Schuhmann Edgar Ventosa Analytical Chemistry - Center for Electroche.mical Sciences (CES) Ruhr-Universitat Bochum Universitasstr. 150 D-44780 Bochum Germany IMDEA Energy Avda. Ramo de la Sagra 3 28935 Motoles Spain

The determination of the intrinsic properties of nanomaterials is essential for their optimization as electrocatalysts, however it poses great challenges from the standpoint of analytical tools and methods. Herein, we report a novel methodology that allows for a binder-free investigation of electrocatalyst nanoparticles. The potential-assisted immobilization of a non-noble metal catalyst, i.e., nickel-iron layered double hydroxide (NiFe LDH) nanoparticles, was employed to directly attach small nanoparticle ensembles from a suspension to the surface of etched carbon nanoelectrodes. The dimensions of this type of electrodes allowed for the immobilization of the catalyst material below the picogram scale and resulted in a high resolution towards the faradaic current response. In addition the effect of the electrochemical aging on the intrinsic activity of the catalyst was investigated in alkaline media by means of continuous cyclic voltammetry. A change in the material properties could be observed, which was accompanied by a substantial decrease in its intrinsic activity.

关键词： oxygen evolution reaction nickel-iron layered double hydroxide (NiFe LDH) immobilization nanoelectrocatalysis nanoelectrodes nanoimpacts

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Mutation D614G increases SARS-CoV-2 transmission

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Signal Transduction and Targeted Therapy 2021年第4期6卷 1075-1076页

作者： Prerna Arora stefan Pohlmann Markus Hoffmann Infection Biology Unit German Primate CenterGottingenGermany Faculty of Biology and Psychology Georg-August-University GottingenGottingenGermany

It has been unclear why SARS-CoV-2 with a D614G mutation in the spike protein became dominant early in the COVID-19 pandemic.A recent study by Hou et *** in Science shows that D614G increases SARS-CoV-2 spread in cult... 详细信息

关键词： 4G D61 spread

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A method for large-scale implantation of 3D microdevice ensembles into brain and soft tissue

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Microsystems & Nanoengineering 2020年第1期6卷 199-211页

作者： stefan A.Sigurdsson Zeyang Yu Joonhee Lee Arto Nurmikko School of Engineering Brown UniversityProvidenceRI 02912USA Department of Neurology Massachusetts General HospitalBostonMA 02114USA Department of Physics and Astronomy West Virginia UniversityMorgantownWV 26506USA Department of Neuroscience West Virginia UniversityMorgantownWV 26506USA

Wireless networks of implantable electronic sensors and actuators at the microscale(sub-mm)level are being explored for monitoring and modulation of physiological activity for medical diagnostics and therapeutic *** the requirement of integrating multiple electronic or chemical functions within small device volumes,a key challenge is the development of high-throughput methods for the implantation of large numbers of microdevices into soft tissues with minimal *** that end,we have developed a method for high-throughput implantation of~100–200µm size devices,which are here simulated by proxy microparticle *** generally applicable to subdermal tissue,our main focus and experimental testbed is the implantation of microparticles into the *** method deploys a scalable delivery tool composed of a 2-dimensional array of polyethylene glycol-tipped microneedles that confine the microparticle *** dissolution of the bioresorbable polyethylene glycol,the supporting array structure is retrieved,and the microparticles remain embedded in the tissue,distributed spatially and geometrically according to the design of the microfabricated delivery *** first evaluated the method in an agarose testbed in terms of spatial precision and throughput for up to 1000 passive spherical and planar microparticles acting as proxy *** then performed the same evaluations by implanting particles into the rat cortex under acute conditions and assessed the tissue injury produced by our method of implantation under chronic conditions.

关键词： implantation method integrating

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Effects of polydispersity on the micro–macro behavior of granular assemblies under different deformation paths

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Particuology 2014年第1期12卷 64-79页

作者： Nishant Kumar Olukayode I.Imole Vanessa Magnanimo stefan Luding Multi Scale Mechanics(MSM) Faculty of Engineering Technology MESA+ University of Twente

The micromechanical and macromechanical behavior of idealized granular assemblies, made by linearly elastic, frictionless, polydisperse spheres, are studied in a periodic, triaxial box geometry, using the dis crete element method. Emphasis is put on the effect of polydispersity under purely isotropic loading and unloading, deviatoric （volume conserving）, and uniaxial compression paths. We show that scaled pressure, coordination number and fraction of rattlers behave in a very similar fashion as functions of volume fraction, irrespective of the deformation path applied. Interestingly, they show a systematic dependence on the deformation mode and polydispersity via the respective jamming volume fraction. This confirms that the concept of a single jamming point has to be rephrased to a range of variable jamming points, dependent on microstructure and history of the sample, making the jamming volume fraction a statevariable. This behavior is confirmed when a simplified constitutive model involving structural anisotropy is calibrated using the purely isotropic and deviatoric simulations. The basic model parameters are found to depend on the polydispersity of the sample through the different jamming volume fractions. The predictive power of the calibrated model is checked by comparison with an independent test, namely uniaxial compression. The important features of the uniaxial experiment are captured and a qualitative prediction for the evolution of stress and fabric is shown involving a ＂softening＂ regime in both stress and fabric stronger for the latter that was not prescribed into the model a priori.

关键词： Polydispersity Anisotropy Deformations Calibration PARDEM

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Routing through open spaces-A performance comparison of algorithms

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Geo-Spatial Information Science 2018年第3期21卷 247-256页

作者： stefan Hahmann Jakob Miksch Bernd Resch Johannes Lauer Alexander Zipf GIScience Research Group Institute of GeographyHeidelberg UniversityHeidelbergGermany Fraunhofer IVI Fraunhofer Institute for Transportation and Infrastructure SystemsDresdenGermany Department of Geoinformatics-Z_GIS University of SalzburgAustria Center for Geographic Analysis Harvard UniversityCambridgeMAUSA HERE GmbH&Co KG Schwalbach am TaunusGermany

Finding the shortest path through open spaces is a well-known challenge for pedestrian routing engines.A common solution is routing on the open space boundary,which causes in most cases an unnecessarily long route.A possible alternative is to create a subgraph within the open *** paper assesses this approach and investigates its implications for routing engines.A number of algorithms(Grid,Spider-Grid,Visibility,Delaunay,Voronoi,Skeleton)have been evaluated by four different criteria:(i)Number of additional created graph edges,(ii)additional graph creation time,(iii)route computation time,(iv)routing *** show that each algorithm has advantages and disadvantages depending on the use *** identify the algorithms Visibility with a reduced number of edges in the subgraph and Spider-Grid with a large grid size to be a good compromise in many scenarios.

关键词： OpenStreetMap routing open space navigation pedestrian polygon

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Electrochemically-stimulated nanoscale mechanochemical wear of silicon

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Friction 2023年第11期11卷 2142-2152页

作者： Chen XIAO stefan VAN VLIET Roland BLIEM Bart WEBER Steve FRANKLIN Advanced Research Center for Nanolithography(ARCNL) Amsterdam 1098XGthe Netherlands Van der Waals–Zeeman Institute Institute of PhysicsUniversity of Amsterdam(UvA)Amsterdam 1098XGthe Netherlands Department of Materials Science and Engineering The University of SheffieldSheffield S13JDUK

Mechanochemical reactions at the sliding interface between a single-crystalline silicon(Si)wafer and a silica(SiO2)microsphere were studied in three environmental conditions:humid air,potassium chloride(KCl)solution,and KCl solution with an applied *** to that from humid air,mechanochemical material removal from the silicon surface increased substantially in the KCl-immersed condition,and further increased when electrochemistry was introduced into the tribological *** measuring the load dependence of the material removal rate and analyzing the results using a mechanically assisted Arrhenius-type kinetic model,the activation energy(E_(a))and the mechanical energy(E_(m)),by which this energy is reduced by mechanical activation,were compared qualitatively under different environmental *** the KCl-immersed condition,mechanochemistry may decrease the required effective energy of reactions(E_(eff)=E_(a)−E_(m))and promote material removal mainly through improved catalysis of the mechanochemical reactions facilitated by greater availability of water molecules compared to the humid air ***,the effectiveness of the mechanochemistry is *** the electrochemical condition,electrochemically-accelerated oxidation of the silicon surface was confirmed by the X-ray photoelectron spectroscopy(XPS)*** results strongly suggest that electrochemistry further stimulates mechanochemical reactions primarily by increasing the initial energy state of the surface via the facilitated formation of interfacial bonding bridges,i.e.,a surface oxidation/hydroxylation process.

关键词： spherical contact adhesive wear normal loading power law

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Patient age and duration of colonoscopy are predictors for adenoma detection in both proximal and distal colon

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World Journal of Gastroenterology 2015年第2期21卷 525-532页

作者： Peter Klare stefan Ascher Alexander Hapfelmeier Petra Wolf Analena Beitz Roland M Schmid stefan von Delius Ⅱ.Medizinische Klinik Klinikum rechts der IsarTechnischen Universit?t München81675 MunichGermany Institut für Medizinische Statistik und Epidemiologie Klinikum rechts der IsarTechnische Universit?t München81675 MunichGermany

AIM: To investigate the relation of patient characteristics and procedural parameters to the endoscopic detection rate of colonic adenomas. Further to study,which factors may be capable to predict the localization of adenomatous ***: We used the data base of a prospective randomized colonoscopy study(The Colo Cap trial) to identify patients being diagnosed with colon adenoma. Logistic regression analysis was conducted to reveal predictors for adenoma detection in the entire colon and also with respect to the proximal and distal part. Covariates including age, gender, duration of colonoscopy and comorbidities were defined to determine association between predictors and adenoma ***: Equal numbers of adenomas were detected in the proximal and distal side of the splenic flexure [126(57%) vs 94(43%), P = 0.104]. Simultaneous occurrence of adenomas in both sides of the colon was rare. The appearance of both proximal and distal adenoma was associated with increasing age(P = 0.008 and P = 0.024) and increasing duration of colonoscopy(P < 0.001 and P = 0.001). Male gender was a predictor for adenoma detection in the proximal colon(P = 0.008) but statistical significance was slightly missed with respect to the distal colon(P = 0.089). Alcohol abuse was found to be a predictor for the detection of distal adenoma(P = 0.041). CONCLUSION: Increasing age and longer duration of colonoscopy are factors with a strong impact on adenoma detection both in the proximal and distal colon. Since proximal adenomas occurred in absence of distal adenomas, complete colonoscopy should be performed for screening.

关键词： Adenoma Colorectal carcinoma Distal Colonoscopy Pr

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Spatial distribution modeling of subsurface bedrock using a developed automated intelligence deep learning procedure:A case study in Sweden

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1300-1310页

作者： Abbas Abbaszadeh Shahri Chunling Shan Emma Zall stefan Larsson Division of Rock Engineering Tyréns ABStockholmSweden Johan Lundberg AB UppsalaSweden Division of Soil and Rock Mechanics KTH Royal Institute of TechnologyStockholmSweden

Due to associated uncertainties,modelling the spatial distribution of depth to bedrock(DTB) is an important and challenging concern in many geo-engineering *** association between DTB,the safety and economy of design structures implies that generating more precise predictive models can be of vital *** the present study,the challenge of applying an optimally predictive threedimensional(3D) spatial DTB model for an area in Stockholm,Sweden was addressed using an automated intelligent computing design *** process was developed and programmed in both C++and Python to track their performance in specified tasks and also to cover a wide variety of diffe rent internal characteristics and *** comparison to the ordinary Kriging(OK) geostatistical tool,the superiority of the developed automated intelligence system was demonstrated through the analysis of confusion matrices and the ranked accuracies of different statistical *** re sults showed that in the absence of measured data,the intelligence models as a flexible and efficient alternative approach can account for associated uncertainties,thus creating more accurate spatial 3D models and providing an appropriate prediction at any point in the subsurface of the study area.

关键词： Automated intelligence system Predictive depth to bedrock(DTB)model Three-dimensional(3D)spatial distribution

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Influence of soil and microclimate on species composition and grass encroachment in heath succession

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Journal of Plant Ecology 2012年第3期5卷 249-259页

作者： Jasmin Mantilla-Contreras Jens Schirmel stefan Zerbe Department of Landscape Ecology Institute of Botany and Landscape EcologyUniversity of GreifswaldGrimmerstrasse 88D-17487 GreifswaldGermany Biological Station of Hiddensee University of GreifswaldBiologenweg 15D-18565 Isle of HiddenseeGermany Faculty of Science and Technology Free University of BolzanoPiazza Universita`5I-39100 Bozen-BolzanoItaly

Aims and Methods Mostly due to land use changes,European heathlands have become increasingly *** addition,the increasing amount of atmospheric nitrogen deposition has resulted in an encroachment of grasses and a loss in species *** many investigations,information about the precise environmental parameters that determine the development and maintenance of heathland vegetation is still *** order to determine the environmental factors that control heath succession and grass encroachment,and to develop appropriate management schemes,we studied the influence of several soil and microclimate parameters on species composition and vegetation characteristics in five successional stages in a coastal heathland on the island of Hiddensee,north-east Germany,where the encroachment of Carex arenaria has become a major *** Findings We recorded the highest plant species richness in grey dune and birch forest plots,while the encroachment of *** let to a significant decline in plant species *** most important environmental factors influencing species richness and distribution of single species were microclimate,soil moisture,soil pH and the C/N *** many studies reported the importance of differences in nutrient availability,we found no significant correlations between soil nutrient availability and vegetation *** conditions in dense *** stands,especially soil properties(*** pH),showed great differences in comparison to the other successional ***,no correlations between the encroachment of *** and single environmental factors were *** results show that not only soil nutrients are important abiotic factors in heaths but that also microclimate and soil moisture play an important role and that many factors are involved in heath succession and in the promotion of grass *** plans for the conservation and restoration of heathlands should therefore focu

关键词： biodiversity Carex arenaria heathland conservation N deposition restoration tall grasses

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