Barth A.,Heidelberg Academy of science and Humanities |
Barth A.,Karlsruhe Institute of Technology |
Wenzel F.,Karlsruhe Institute of Technology
Tectonophysics | Year: 2010
The Amurian plate plays an important role for the understanding of eastern Asian plate dynamics. Different models of rigid-rotation and relative velocities with respect to adjacent plates have been proposed. As few GPS data and sparse stress observations have been available until today-particularly for the intraplate region-these models have proven hard to confirm or deny. To address this we determine new focal mechanisms for this region and perform a stress inversion for selected parts of the plate in order to provide better constraints on the plate dynamics. Most strong earthquakes occur on active plate margins and for these events focal mechanisms are routinely calculated by moment tensor inversion using teleseismic data on a global scale. Away from the plate margins, earthquake magnitudes are smaller and the efficiency of such automated procedures strongly depends on the number of seismic records available. Using the Frequency Sensitive Moment Tensor Inversion allows us to determine source mechanisms of light events with a smaller number of data. For the Amurian plate interior, we calculate 41 focal mechanisms for crustal earthquakes from 1993 to 2008 (3.9 ≤ MW ≤ 5.4). We combine these data with additional solutions from the literature to perform formal stress inversions for three separate regions. The reliability of the resulting stress orientations is evaluated by bootstrap analysis to show the variability of the principle stress axes. For all regions the resulting stress field shows a dominant strike-slip regime with an ENE-WSW orientation of the maximum horizontal compressional stress SH and is consistent with borehole stress data from the World Stress Map at the margins and in the central part of the Amurian plate. Moreover, our analysis reveals differences in both the stress ratio and the SH orientation within the plate interior. While the northern part of the Amurian plate might be influenced by the Baikal rift in terms of a small anti-clockwise rotation of SH, the eastern part of the plate clearly responds to the far field plate-boundary forces from the subducting Pacific plate. © 2009 Elsevier B.V. All rights reserved.
Will M.,University of Tubingen |
Parkington J.E.,University of Cape Town |
Kandel A.W.,Heidelberg Academy of science and Humanities |
Conard N.J.,University of Tubingen
Journal of Human Evolution | Year: 2013
New excavations at the Middle Stone Age (MSA) open-air site of Hoedjiespunt 1 (HDP1) on the west coast of South Africa advance our understanding of the evolution of coastal adaptations in Homo sapiens. The archaeological site of HDP1 dates to the last interglacial and consists of three phases of occupation, each containing abundant lithic artifacts, shellfish, terrestrial fauna, ostrich eggshell and pieces of ground ocher. The site provides an excellent case study to analyze human behavioral adaptations linked to early exploitation of marine resources. Here we reconstruct human activities through a detailed study of the lithic assemblages, combining analyses of the reduction sequences, artifact attributes and quartz fracturing. These methods provide insights into raw material procurement, lithic reduction sequences, site use and mobility patterns, and foster comparison with other MSA coastal sites. The main characteristics of the lithic assemblages remain constant throughout the use of the site. Quartz dominates silcrete and other raw materials by almost four to one. Knappers at HDP1 produced different forms of flakes using multiple core reduction methods. Denticulates represent the most frequent tool type. The assemblages document complete, bipolar and hard hammer reduction sequences for the locally available quartz, but highly truncated reduction sequences with many isolated end products for silcrete, a material with a minimum transport distance of 10-30. km. This observation suggests that well provisioned individuals executed planned movements to the shoreline to exploit shellfish. Our excavations at HDP1 furthermore demonstrate the simultaneous occurrence of flexible raw material use, anticipated long-distance transport, systematic gathering of shellfish and use of ground ocher. The HDP1 lithic assemblages document a robust pattern of land-use that we interpret as a stable adaptation of modern humans to coastal landscapes as early as MIS 5e. © 2013 Elsevier Ltd.
Reinecker J.,University of Tubingen |
Tingay M.,Curtin University Australia |
Muller B.,Heidelberg Academy of science and Humanities |
Muller B.,Karlsruhe Institute of Technology |
Heidbach O.,Karlsruhe Institute of Technology
Tectonophysics | Year: 2010
The present-day state of stress in Western Europe is considered to be controlled by forces acting at the plate boundaries. It is assumed that the Alpine orogen only influence the regional pattern of present-day stress in Western Europe within the Alps themselves. We examine the present-day maximum horizontal stress orientation in the Molasse Basin in the Alpine foreland in order to investigate the possible influence of the Alps on the far-field stress pattern of Western Europe. Four-arm caliper and image logs were analysed in 137 wells, in which a total of 1348 borehole breakouts and 59 drilling-induced fractures were observed in 98 wells in the German Molasse Basin. The borehole breakouts and drilling-induced fractures reveal that stress orientations are highly consistent within the Molasse Basin and that the present-day maximum horizontal stress orientation rotates from N-S in southeast Germany (002°N ± 19°) to approximately NNW-SSE in southwest Germany and the Swiss Molasse Basin (150°N ± 24°). The present-day maximum horizontal stress orientation in the Molasse Basin is broadly perpendicular to the strike of the Alpine front, indicating that the stress pattern is probably controlled by gravitational potential energy of Alpine topography rather than by plate boundary forces. The present-day maximum horizontal stress orientations determined herein have important implications for the production of hydrocarbons and geothermal energy in the German Molasse Basin, in particular that hydraulically-induced fractures are likely to propagate N-S and that wells deviated to the north or south may have reduced wellbore instability problems. © 2009 Elsevier B.V. All rights reserved.
Bork S.,University of Heidelberg |
Bork S.,Heidelberg Academy of science and Humanities |
Horn P.,University of Heidelberg |
Castoldi M.,University of Heidelberg |
And 4 more authors.
Journal of Cellular Physiology | Year: 2011
Long-term culture of human mesenchymal stromal cells (MSC) has implications on their proliferation and differentiation potential and we have demonstrated that this is associated with up-regulation of the five microRNAs miR-29c, miR-369-5p, miR-371, miR-499, and let-7f. In this study, we examined the role of these senescence-associated microRNAs for cellular aging and differentiation of MSC. Proliferation was reduced upon transfection with miR-369-5p, miR-371, and miR-499. Adipogenic differentiation was impaired by miR-369-5p whereas it was highly increased by miR-371. This was accompanied by respective gene expression changes of some adipogenic key molecules (adiponectin and fatty acid-binding protein 4 [FABP4]). Furthermore luciferase reporter assay indicated that FABP4 is a direct target of miR-369-5p. Microarray analysis upon adipogenic or osteogenic differentiation revealed down-regulation of several microRNAs albeit miR-369-5p and miR-371 were not affected. Expression of the de novo DNA methyltransferases DNMT3A and DNMT3B was up-regulated by transfection of miR-371 whereas expression of DNMT3A was down-regulated by miR-369-5p. In summary, we identified miR-369-5p and miR-371 as antagonistic up-stream regulators of adipogenic differentiation and this might be indirectly mediated by epigenetic modifications. © 2010 Wiley-Liss, Inc.
Schweiker M.,Karlsruhe Institute of Technology |
Schweiker M.,Heidelberg Academy of science and Humanities |
Wagner A.,Karlsruhe Institute of Technology
Energy and Buildings | Year: 2016
Agent-based modeling (ABM) allows implementing negotiated behaviors between individual agents. Little is known on how individually preferred behavioral patterns adapt within office spaces used by multiple people. Even less is known about the effect of such negotiated behaviors on the occupants' satisfaction in terms of preferred indoor thermal conditions and the level of perceived control. In order to gain insights into these processes, an experimental study in a field laboratory was conducted. The 36 subjects worked in the facility for three days: one day in a single person office, one in an office for two people, and one in an office for four people. They were allowed to tilt windows, close blinds, use a ceiling fan, or adjust their clothing levels. The data was analyzed quantitatively and qualitatively. The results suggest that perceived control is negatively affected by the number of people, neutral temperatures are negatively affected by a lack of perceived control, actions on windows are increasing and actions on blinds and fans are decreasing. Based on the results, suggestions for advancements of ABM are given. However, further studies - especially field studies - are necessary before these results can be applied to models applicable for a broader usage. © 2015 Elsevier B.V.