Rock Glacier Characteristics Under Semiarid Climate Conditions in the Western Nyainqêntanglha Range, Tibetan Plateau

Abstract Rock glaciers are receiving increased attention as a potential source of water and indicator of climate change in periglacial landscapes. They consist of an ice‐debris mixture, which creeps downslope. Although rock glaciers are a wide‐spread feature on the Tibetan Plateau, characteristics such as its ice fraction are unknown as a superficial debris layer inhibits remote assessments. We investigate one rock glacier in the semiarid western Nyainqêntanglha range (WNR) with a multi‐method approach, which combines geophysical, geological and geomorphological field investigations with remote sensing techniques. Long‐term kinematics of the rock glacier are detected by 4‐year InSAR time series analysis. The ice content and the active layer are examined by electrical resistivity tomography, ground penetrating radar, and environmental seismology. Short‐term activity (11‐days) is captured by a seismic network. Clast analysis shows a sorting of the rock glacier's debris. The rock glacier has three zones, which are defined by the following characteristics: (a) Two predominant lithology types are preserved separately in the superficial debris patterns, (b) heterogeneous kinematics and seismic activity, and (c) distinct ice fractions. Conceptually, the studied rock glacier is discussed as an endmember of the glacier—debris‐covered glacier—rock glacier continuum. This, in turn, can be linked to its location on the semiarid lee‐side of the mountain range against the Indian summer monsoon. Geologically preconditioned and glacially overprinted, the studied rock glacier is suggested to be a recurring example for similar rock glaciers in the WNR. This study highlights how geology, topography and climate influence rock glacier characteristics and development.Plain Language Summary Climate change has begun to impact all regions of our planet. In cold regions, such as high‐mountain areas, rising temperatures lead to massive melting of glaciers. Besides this evident loss of ice, permafrost, a long‐term ice resource hidden in the subsurface, has started to thaw. Rock glaciers as visible permafrost‐related landforms consist of an ice‐debris mixture, which makes them creep downslope. Due to this movement and their recognizable shape, rock glaciers are permafrost indicators in high‐mountain areas. We investigate one rock glacier in the western Nyaingêntanglha Range (Tibetan Plateau) using field and remote sensing methods to understand its development and to know the current state of its ice core. Our main outcome is, that the heterogeneous creeping behavior, the properties of the debris cover as well as the internal distribution of ice are the results of a continuous development from a glacier into today's rock glacier. In particular, the high ice content in particular sections points to such a glacial precondition. The debris layer covering the internal ice attenuates the effect of climate warming. This makes the rock glacier and similar rock glaciers found in the northern part of the mountain range important future water resources for the semiarid region.Key Points Geophysical and remote sensing methods in concert reveal the morphostructure, ice fraction, and kinematics of the studied rock glacier Rock glacier characteristics are controlled by geology, topography and climate on the Tibetan Plateau The studied rock glacier is conceptually interpreted as the endmember of a glacier—debris‐covered glacier—rock glacier continuu

In situ strain detection of stress-strain relationships and their controls on progressive damage in marble and quartzite by neutron diffraction experiments

The application of data derived from rock mechanical experiments to large spatial and temporal scales required to assess rock slope stability and landscape evolution is complicated, as these processes of rocks are affected by its lithology, tectonic heritage and rheological behavior under the contemporary stress field. Interpretations of experiments and field sites are restricted to surficial, pre and post state observations of deformations, under almost always subcritical near surface stress fields. We set up an novel experiment to quantify a) the level of inherited residual elastic strains, b) the effect of subcritical low magnitude load steps, c) load magnitudes at which deformation become permanent and further strains are induced and d) differences of rheological behavior due to lithology. In order to gain greater insight into the stress-strain relationships and their control on progressive damage we employed in situ neutron diffraction techniques to observe crystal lattice strains in pure marble (Carrara marble, > 98 vol% CaCO3) and quartzite (Dalsland quartzite, > 98 vol% SiO2) samples during stepped Brazilian tests. We measure a gauge volume of ∼42mm3 in the center of cylindrical samples (Ø= 30 mm, l = 22 mm quartzite, l = 26 mm marble) using the EPSILON neutron time-of-flight (TOF) strain diffractometer in Dubna, Russia. Surface-mounted strain gauges provide macroscopic strain data, and acoustic emission sensors are used to detect microcrack initiation. Initial states are measured without load to determine the load-free lattice parameters. Load is increased in three to four stages of approximately 15%, 33%, 66%, and 75-80% of the ultimate intact rock strength (σ1 max), and maintained during diffraction measurements (up to 12 hours each). Each load step is followed by a load-free state. Deviatoric strain in both major principal compressive (σ1) and minor principal in plane (σ3) direction, as well as residual strain, with reference to a strain-free state of powdered samples are calculated for whole diffraction patterns. We obtained initial residual contractional strains of ∼-150 μstrain for Carrara marble and of ∼-50 μstrain for the Dalsland quartzite samples. Already during the first load step of ∼10-15% σ1 max superposition of the residual strain state is observed and strains partially remain during unloading step. Increased stress magnitudes of the load steps enable us to identify strains as a function of external load and subsequent unloading, indicating, in both rocks, that upon unloading from former loads to less than 75% σ1 max, the material remains partially extensionally strained

Instabilities in crystal growth by atomic or molecular beams

The planar front of a growing a crystal is often destroyed by instabilities. In the case of growth from a condensed phase, the most frequent ones are diffusion instabilities, which will be but briefly discussed in simple terms in chapter II. The present review is mainly devoted to instabilities which arise in ballistic growth, especially Molecular Beam Epitaxy (MBE). The reasons of the instabilities can be geometric (shadowing effect), but they are mostly kinetic or thermodynamic. The kinetic instabilities which will be studied in detail in chapters IV and V result from the fact that adatoms diffusing on a surface do not easily cross steps (Ehrlich-Schwoebel or ES effect). When the growth front is a high symmetry surface, the ES effect produces mounds which often coarsen in time according to power laws. When the growth front is a stepped surface, the ES effect initially produces a meandering of the steps, which eventually may also give rise to mounds. Kinetic instabilities can usually be avoided by raising the temperature, but this favours thermodynamic instabilities. Concerning these ones, the attention will be focussed on the instabilities resulting from slightly different lattice constants of the substrate and the adsorbate. They can take the following forms. i) Formation of misfit dislocations (chapter VIII). ii) Formation of isolated epitaxial clusters which, at least in their earliest form, are `coherent' with the substrate, i.e. dislocation-free (chapter X). iii) Wavy deformation of the surface, which is presumably the incipient stage of (ii) (chapter IX). The theories and the experiments are critically reviewed and their comparison is qualitatively satisfactory although some important questions have not yet received a complete answer.Comment: 90 pages in revtex, 45 figures mainly in gif format. Review paper to be published in Physics Reports. Postscript versions for all the figures can be found at http://www.theo-phys.uni-essen.de/tp/u/politi

Rehabilitative Versorgung und gesundheitsbedingte Frühberentung von Personen mit Migrationshintergrund in Deutschland: Abschlussbericht

Dieser Abschlussbericht stellt die Ergebnisse des Projektes "Rehabilitative Versorgung und gesundheitsbedingte Frühberentung von Personen mit Migrationshintergrund in Deutschland" vor. Auf Basis eines quantitativen und qualitativen Forschungszugangs wurde untersucht, inwiefern sich einzelne Gruppen von ausländischen Staatsangehörigen bzw. Menschen mit Migrationshintergrund hinsichtlich der Häufigkeit von Arbeitsunfällen und Berufskrankheiten, der Inanspruchnahme beruflicher und medizinischer Rehabilitationsmaßnahmen, des Rehabilitationserfolges und der Frühberentung von Deutschen bzw. Menschen ohne Migrationshintergrund unterscheiden. Unter Bezugnahme auf Prozess- und Individualdaten unterschiedlicher Rehabilitationsträger zeigt der Bericht, dass Menschen mit Migrationshintergrund im Durchschnitt weniger häufig Maßnahmen der medizinischen Rehabilitation in Anspruch nehmen sowie einen geringeren Rehabilitationserfolg und höhere Frühberentungsquoten aufweisen als die Mehrheitsbevölkerung. Auf Basis einer systematischen Literaturrecherche und mittels qualitativer Experten- und Fokusgruppeninterviews werden darüber hinaus unterschiedliche Zugangs-, Durchführungs- und Wirksamkeitsbarrieren in der Rehabilitation von Menschen mit Migrationshintergrund identifiziert, welche die quantitativen Ergebnisse zumindest teilweise erklären können. Handlungsempfehlungen für die Verbesserung der rehabilitativen Versorgung von Menschen mit Migrationshintergrund werden abgeleitet

Cross-realm assessment of climate change impacts on species' abundance trends

Climate change, land-use change, pollution and exploitation are among the main drivers of species' population trends; however, their relative importance is much debated. We used a unique collection of over 1,000 local population time series in 22 communities across terrestrial, freshwater and marine realms within central Europe to compare the impacts of long-term temperature change and other environmental drivers from 1980 onwards. To disentangle different drivers, we related species' population trends to species- and driver-specific attributes, such as temperature and habitat preference or pollution tolerance. We found a consistent impact of temperature change on the local abundances of terrestrial species. Populations of warm-dwelling species increased more than those of cold-dwelling species. In contrast, impacts of temperature change on aquatic species' abundances were variable. Effects of temperature preference were more consistent in terrestrial communities than effects of habitat preference, suggesting that the impacts of temperature change have become widespread for recent changes in abundance within many terrestrial communities of central Europe.Additionally, we appreciate the open access marine data provided by the International Council for the Exploration of the Sea. We thank the following scientists for taxonomic or technical advice: C. Brendel, T. Caprano, R. Claus, K. Desender, A. Flakus, P. R. Flakus, S. Fritz, E.-M. Gerstner, J.-P. Maelfait, E.-L. Neuschulz, S. Pauls, C. Printzen, I. Schmitt and H. Turin, and I. Bartomeus for comments on a previous version of the manuscript. R.A. was supported by the EUproject LIMNOTIP funded under the seventh European Commission Framework Programme (FP7) ERA-Net Scheme (Biodiversa, 01LC1207A) and the long-term ecological research program at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB). R.W.B. was supported by the Scottish Government Rural and Environment Science and Analytical Services Division (RESAS) through Theme 3 of their Strategic Research Programme. S.D. acknowledges support of the German Research Foundation DFG (grant DO 1880/1-1). S.S. acknowledges the support from the FP7 project EU BON (grant no. 308454). S.K., I.Kü. and O.S. acknowledge funding thorough the Helmholtz Association’s Programme Oriented Funding, Topic ‘Land use, biodiversity, and ecosystem services: Sustaining human livelihoods’. O.S. also acknowledges the support from FP7 via the Integrated Project STEP (grant no. 244090). D.E.B. was funded by a Landes–Offensive zur Entwicklung Wissenschaftlich–ökonomischer Exzellenz (LOEWE) excellence initiative of the Hessian Ministry for Science and the Arts and the German Research Foundation (DFG: Grant no. BO 1221/23-1).Peer Reviewe

Verschlechterte Bedingungen für die Wohnungswirtschaft [dt. und engl.]

Mit dem Steuervergünstigungsabbaugesetz soll eine Veräußerungsgewinnsteuer auf privates Vermögen eingeführt werden. Eine solche Steuer passt nicht in die Steuersystematik, weil damit ein drittes Mal auf Vermögensanlagen zugegriffen wird. Betroffen sind oft langfristig angelegte Investitionsentscheidungen, u.a. zur Alterssicherung. Die Steuer steht damit im Widerspruch zu den unternommenen Anstrengungen, Ersparnisse im Rahmen der Altersvorsorge nur noch einmal zu besteuern. Lediglich die Kürzung der Eigenheimzulage kann als echter Abbau von Subventionen gesehen werden. Die Kürzung sollte jedoch nicht zu abrupt, sondern mit zeitlicher Verzögerung erfolgen. Gemeinsame Studie des Instituts für Wohnungswirtschaft und Wohnungsrecht und Deutsche Bank Research

Die Inanspruchnahme medizinischer Rehabilitation bei Menschen mit Migrationshintergrund

Voigtländer S, Brzoska P, Spallek J, Exner AK, Razum O. Die Inanspruchnahme medizinischer Rehabilitation bei Menschen mit Migrationshintergrund. In: Schott TP, Razum O, eds. Migration und medizinische Rehabilitation. Gesundheitsforschung. Weinheim, Basel: Beltz Juventa Verlag; 2013: 92-104

Calcite Twinning in Mollusk Shells and Carrara Marble

Mollusk shells protect the animals that form and inhabit them. They are composites of minerals and organics, with diverse mesostructures, including nacre, prismatic calcite, crossed-lamellar aragonite, and foliated calcite. Twins, that is, crystals mirror symmetric with respect to their coherent interface, occurring as formation or deformation twins, are observed in all mollusk shell mesostructures but never within calcite prisms. Here, nanotwins and microwins within single calcite prisms are observed in different shells. Using Polarization-dependent Imaging Contrast (PIC) mapping with 20–60 nm resolution, twins are observed to be 0.2–3 µm thick layers of differently oriented and colored crystals with respect to the main prism crystal. Multiple twins are interspersed with the prism crystal, parallel to one another, and similarly oriented. When comparing images of calcite prisms and twins obtained by PIC mapping and by Electron Back-Scattered Diffraction (EBSD), the images correspond precisely. All twins are e-twin types, with 127° angular distance between c-axes. E-twins are the most common deformation twins in geologic calcite, as also observed here in Carrara marble. Location of all twins near the outer surface of all shells and e-twin type both suggest that twins within calcite prisms in mollusk shells result from deformation twinning

In-situ strain detection of stress-strain relationships and their controls on progressive damage in marble and quartzite by neutron diffraction experiments

ISSN:1029-7006ISSN:1607-796

Rock slope failure preparation paced by total crack boundary length

International audienceGravitational mass wasting prediction requires understanding of the factors controlling failure. Prior to slope failure, cracks in the weakened rock are thought to grow and coalesce, eventually forming a continuous failure plane. Here, we apply a hidden Markov machine learning model to seismic data, revealing the temporal evolution of cracks prior to a major rockslide event in the Swiss Alps. After prolonged linear increase of the crack cumulative number, an S-shaped crack rate pattern occurred in the day before the rockslide. A simple mechanistic model can explain this behaviour, showing that total crack boundary length is the key factor controlling failure plane evolution immediately before mass movement. Our findings imply that cracks should be treated as 2-D, rather than 1-D objects, and that slope failure can be driven predominantly by internal rather than external processes. Our model offers a novel, physically based approach for early warning of slope failures