0000000000522731

AUTHOR

Johannes Klein

showing 6 related works from this author

The Influence of Crystal Size Distributions on the Rheology of Magmas: New Insights From Analog Experiments

2017

This study examines the influence of particle size distributions on the rheology of particle suspensions by using analogue experiments with spherical glass beads in silicone oil as magma equivalent. The analyses of 274 individual particle-bearing suspensions of varying modality (uni-, bi- tri- and tetramodality), as well as of polymodal suspensions with specific defined skewness and variance, are the first data set of its kind and provide important insights in the relationship between the solid particles of a suspension and its rheological behaviour. Since the relationship between the rheology of particle bearing suspensions and its maximum packing fraction ϕm is well established by several…

010504 meteorology & atmospheric sciencesDispersityMineralogyThermodynamics010502 geochemistry & geophysicsAtomic packing factor01 natural sciencesViscosityGeophysicsRheologyGeochemistry and PetrologyParticle-size distributionParticleParticle sizeSuspension (vehicle)Geology0105 earth and related environmental sciencesGeochemistry, Geophysics, Geosystems
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Which changes are needed to render all genera of the German lora monophyletic?

2016

53 p., gráf.

0106 biological sciencesSystematicsFloraPhylogenetic treeZoologyPlant ScienceBiologyClassification010603 evolutionary biology01 natural scienceslanguage.human_languageGermanGeneric circumscriptionMonophylyTaxonGerman floraPhylogeneticslanguageMonophylyEcology Evolution Behavior and SystematicsPhylogeny010606 plant biology & botany
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Linnaeus's folly – phylogeny, evolution and classification ofSedum(Crassulaceae) and Crassulaceae subfamily Sempervivoideae

2020

SubfamilybiologyMolecular datingPhylogeneticsBotanyPlant Sciencebiology.organism_classificationEcology Evolution Behavior and SystematicsSedumCrassulaceaeTAXON
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Increased Arterial Augmentation and Augmentation Index as Surrogate Parameters for Arteriosclerosis in Subjects with Diabetes Mellitus and Nondiabeti…

2007

Background: Arterial augmentation (AP) and the augmentation index (Aix) are surrogate parameters of arterial stiffness and are commonly used as predictors for cardiovascular risk. The aim of this study is to compare these parameters in diabetic subjects and nondiabetic cardiovascular risk subjects with healthy control subjects. Methods: One hundred sixty-six nonsmoking subjects aged between 35 and 70 years were included in the study, which included 100 subjects with cardiovascular disease but not diabetes (mean age 62.73±8.75 years), 33 subjects with type 2 diabetes (66.58±2.69 years), and 33 healthy controls (51.89±8.91 years). In these subjects, arterial stiffness was measured by the diff…

Neurological and Microvascular Functionmedicine.medical_specialtybusiness.industryEndocrinology Diabetes and MetabolismBiomedical EngineeringCentral pressure030209 endocrinology & metabolismBioengineeringMean ageArteriosclerosisDiseaseType 2 diabetesmedicine.disease03 medical and health sciences0302 clinical medicineEndocrinologyDiabetes mellitusInternal medicineHealthy controlInternal MedicinemedicineArterial stiffnessCardiology030212 general & internal medicinebusinessJournal of Diabetes Science and Technology
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The evolutionary history of the Arabidopsis arenosa complex: diverse tetraploids mask the Western Carpathian center of species and genetic diversity.

2012

The Arabidopsis arenosa complex is closely related to the model plant Arabidopsis thaliana. Species and subspecies in the complex are mainly biennial, predominantly outcrossing, herbaceous, and with a distribution range covering most parts of latitudes and the eastern reaches of Europe. In this study we present the first comprehensive evolutionary history of the A. arenosa species complex, covering its natural range, by using chromosome counts, nuclear AFLP data, and a maternally inherited marker from the chloroplast genome [trnL intron (trnL) and trnL/F intergenic spacer (trnL/F-IGS) of tRNA(Leu) and tRNA(Phe), respectively]. We unravel the broad-scale cytogeographic and phylogeographic pa…

Species complexAngiospermsPlant EvolutionScienceArabidopsisPopulation geneticsOutcrossingPlant ScienceSubspeciesPlant GeneticsChromosomes PlantArabidopsis arenosaSpecies SpecificityBotanyIce CoverEvolutionary SystematicsAmplified Fragment Length Polymorphism AnalysisBiologyTaxonomyEcotypeGenetic diversityPrincipal Component AnalysisEvolutionary BiologyMultidisciplinaryEcotypebiologyBase SequenceGeographyQRDNA ChloroplastGenetic VariationComputational BiologyPlant TaxonomyPlantsbiology.organism_classificationBiological EvolutionDiploidyEuropeTetraploidyPhylogeographyddc:580HaplotypesBiogeographyEarth SciencesMedicinePopulation GeneticsResearch ArticlePloS one
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An expanded model and application of the combined effect of crystal-size distribution and crystal shape on the relative viscosity of magmas

2018

International audience; This study examines the combined effect of crystal-size distributions (CSD) and crystal shape on the rheology of vesicle free magmatic suspensions and provides the first practical application of an empirical model to estimate the relative effect of crystal content and CSD's on the viscosity of magma directly from textural image analysis of natural rock samples in the form of a user-friendly texture-rheology spreadsheet calculator. We extend and apply established relationships between the maximum packing fraction ϕm of a crystal bearing suspension and both its rheological properties and the polydispersity γ of a CSD. By using analogue rotational rheometric experiments…

010504 meteorology & atmospheric sciencesRelative viscosityDispersityThermodynamicsMagma rheologyCrystal size distribution010502 geochemistry & geophysicsAtomic packing factor01 natural sciencesCrystalViscosityGeophysicsRheologyGeochemistry and PetrologyMagma[SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/VolcanologySuspension (vehicle)GeologyCrystal shape0105 earth and related environmental sciences
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