TY - JOUR A1 - Ströhl, D. A1 - Thomas, Steffen A1 - Radeglia, R. A1 - Brunn, J. A1 - Kleinpeter, Erich T1 - 13C-NMR-Untersuchungen von Substituenteneffekten in mehrfach substituierten Benz-und Naphthalenderivaten ; Inkrementberechnungen der 13C-chemischen Verschiebungen Y1 - 1992 ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Thomas, Steffen A1 - Uhlig, G. A1 - Rudorf, Wolf-Dieter T1 - Study of the distribution of pi-Electrons in Push-Pull Alkenes by 1H an 13C NMR spectroscopy Y1 - 1993 ER - TY - JOUR A1 - Gossner, Martin M. A1 - Lewinsohn, Thomas M. A1 - Kahl, Tiemo A1 - Grassein, Fabrice A1 - Boch, Steffen A1 - Prati, Daniel A1 - Birkhofer, Klaus A1 - Renner, Swen C. A1 - Sikorski, Johannes A1 - Wubet, Tesfaye A1 - Arndt, Hartmut A1 - Baumgartner, Vanessa A1 - Blaser, Stefan A1 - Blüthgen, Nico A1 - Börschig, Carmen A1 - Buscot, Francois A1 - Diekötter, Tim A1 - Jorge, Leonardo Re A1 - Jung, Kirsten A1 - Keyel, Alexander C. A1 - Klein, Alexandra-Maria A1 - Klemmer, Sandra A1 - Krauss, Jochen A1 - Lange, Markus A1 - Müller, Jörg A1 - Overmann, Jörg A1 - Pasalic, Esther A1 - Penone, Caterina A1 - Perovic, David J. A1 - Purschke, Oliver A1 - Schall, Peter A1 - Socher, Stephanie A. A1 - Sonnemann, Ilja A1 - Tschapka, Marco A1 - Tscharntke, Teja A1 - Türke, Manfred A1 - Venter, Paul Christiaan A1 - Weiner, Christiane N. A1 - Werner, Michael A1 - Wolters, Volkmar A1 - Wurst, Susanne A1 - Westphal, Catrin A1 - Fischer, Markus A1 - Weisser, Wolfgang W. A1 - Allan, Eric T1 - Land-use intensification causes multitrophic homogenization of grassland communities JF - Nature : the international weekly journal of science N2 - Land-use intensification is a major driver of biodiversity loss(1,2). Alongside reductions in local species diversity, biotic homogenization at larger spatial scales is of great concern for conservation. Biotic homogenization means a decrease in beta-diversity (the compositional dissimilarity between sites). Most studies have investigated losses in local (alpha)-diversity(1,3) and neglected biodiversity loss at larger spatial scales. Studies addressing beta-diversity have focused on single or a few organism groups (for example, ref. 4), and it is thus unknown whether land-use intensification homogenizes communities at different trophic levels, above-and belowground. Here we show that even moderate increases in local land-use intensity (LUI) cause biotic homogenization across microbial, plant and animal groups, both above- and belowground, and that this is largely independent of changes in alpha-diversity. We analysed a unique grassland biodiversity dataset, with abundances of more than 4,000 species belonging to 12 trophic groups. LUI, and, in particular, high mowing intensity, had consistent effects on beta-diversity across groups, causing a homogenization of soil microbial, fungal pathogen, plant and arthropod communities. These effects were nonlinear and the strongest declines in beta-diversity occurred in the transition from extensively managed to intermediate intensity grassland. LUI tended to reduce local alpha-diversity in aboveground groups, whereas the alpha-diversity increased in belowground groups. Correlations between the alpha-diversity of different groups, particularly between plants and their consumers, became weaker at high LUI. This suggests a loss of specialist species and is further evidence for biotic homogenization. The consistently negative effects of LUI on landscape-scale biodiversity underscore the high value of extensively managed grasslands for conserving multitrophic biodiversity and ecosystem service provision. Indeed, biotic homogenization rather than local diversity loss could prove to be the most substantial consequence of land-use intensification. Y1 - 2016 U6 - https://doi.org/10.1038/nature20575 SN - 0028-0836 SN - 1476-4687 VL - 540 SP - 266 EP - + PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Allan, Eric A1 - Bossdorf, Oliver A1 - Dormann, Carsten F. A1 - Prati, Daniel A1 - Gossner, Martin M. A1 - Tscharntke, Teja A1 - Blüthgen, Nico A1 - Bellach, Michaela A1 - Birkhofer, Klaus A1 - Boch, Steffen A1 - Böhm, Stefan A1 - Börschig, Carmen A1 - Chatzinotas, Antonis A1 - Christ, Sabina A1 - Daniel, Rolf A1 - Diekötter, Tim A1 - Fischer, Christiane A1 - Friedl, Thomas A1 - Glaser, Karin A1 - Hallmann, Christine A1 - Hodac, Ladislav A1 - Hölzel, Norbert A1 - Jung, Kirsten A1 - Klein, Alexandra-Maria A1 - Klaus, Valentin H. A1 - Kleinebecker, Till A1 - Krauss, Jochen A1 - Lange, Markus A1 - Morris, E. Kathryn A1 - Müller, Jörg A1 - Nacke, Heiko A1 - Pasalic, Esther A1 - Rillig, Matthias C. A1 - Rothenwoehrer, Christoph A1 - Schally, Peter A1 - Scherber, Christoph A1 - Schulze, Waltraud X. A1 - Socher, Stephanie A. A1 - Steckel, Juliane A1 - Steffan-Dewenter, Ingolf A1 - Türke, Manfred A1 - Weiner, Christiane N. A1 - Werner, Michael A1 - Westphal, Catrin A1 - Wolters, Volkmar A1 - Wubet, Tesfaye A1 - Gockel, Sonja A1 - Gorke, Martin A1 - Hemp, Andreas A1 - Renner, Swen C. A1 - Schöning, Ingo A1 - Pfeiffer, Simone A1 - König-Ries, Birgitta A1 - Buscot, Francois A1 - Linsenmair, Karl Eduard A1 - Schulze, Ernst-Detlef A1 - Weisser, Wolfgang W. A1 - Fischer, Markus T1 - Interannual variation in land-use intensity enhances grassland multidiversity JF - Proceedings of the National Academy of Sciences of the United States of America N2 - Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation. KW - biodiversity loss KW - agricultural grasslands KW - Biodiversity Exploratories Y1 - 2014 U6 - https://doi.org/10.1073/pnas.1312213111 SN - 0027-8424 VL - 111 IS - 1 SP - 308 EP - 313 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Kurpiers, Jona A1 - Ferron, Thomas A1 - Roland, Steffen A1 - Jakoby, Marius A1 - Thiede, Tobias A1 - Jaiser, Frank A1 - Albrecht, Steve A1 - Janietz, Silvia A1 - Collins, Brian A. A1 - Howard, Ian A. A1 - Neher, Dieter T1 - Probing the pathways of free charge generation in organic bulk heterojunction solar cells JF - Nature Communications N2 - The fact that organic solar cells perform efficiently despite the low dielectric constant of most photoactive blends initiated a long-standing debate regarding the dominant pathways of free charge formation. Here, we address this issue through the accurate measurement of the activation energy for free charge photogeneration over a wide range of photon energy, using the method of time-delayed collection field. For our prototypical low bandgap polymer:fullerene blends, we find that neither the temperature nor the field dependence of free charge generation depend on the excitation energy, ruling out an appreciable contribution to free charge generation though hot carrier pathways. On the other hand, activation energies are on the order of the room temperature thermal energy for all studied blends. We conclude that charge generation in such devices proceeds through thermalized charge transfer states, and that thermal energy is sufficient to separate most of these states into free charges. Y1 - 2018 U6 - https://doi.org/10.1038/s41467-018-04386-3 SN - 2041-1723 VL - 9 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Sini, Gjergji A1 - Schubert, Marcel A1 - Risko, Chad A1 - Roland, Steffen A1 - Lee, Olivia P. A1 - Chen, Zhihua A1 - Richter, Thomas V. A1 - Dolfen, Daniel A1 - Coropceanu, Veaceslav A1 - Ludwigs, Sabine A1 - Scherf, Ullrich A1 - Facchetti, Antonio A1 - Frechet, Jean M. J. A1 - Neher, Dieter T1 - On the Molecular Origin of Charge Separation at the Donor-Acceptor Interface JF - Advanced energy materials N2 - Fullerene-based acceptors have dominated organic solar cells for almost two decades. It is only within the last few years that alternative acceptors rival their dominance, introducing much more flexibility in the optoelectronic properties of these material blends. However, a fundamental physical understanding of the processes that drive charge separation at organic heterojunctions is still missing, but urgently needed to direct further material improvements. Here a combined experimental and theoretical approach is used to understand the intimate mechanisms by which molecular structure contributes to exciton dissociation, charge separation, and charge recombination at the donor-acceptor (D-A) interface. Model systems comprised of polythiophene-based donor and rylene diimide-based acceptor polymers are used and a detailed density functional theory (DFT) investigation is performed. The results point to the roles that geometric deformations and direct-contact intermolecular polarization play in establishing a driving force ( energy gradient) for the optoelectronic processes taking place at the interface. A substantial impact for this driving force is found to stem from polymer deformations at the interface, a finding that can clearly lead to new design approaches in the development of the next generation of conjugated polymers and small molecules. KW - donor-acceptor interfaces KW - energy gradients KW - geometrical deformations KW - nonfullerene acceptors KW - organic photovoltaics KW - photocurrent generation KW - polymer solar cells Y1 - 2018 U6 - https://doi.org/10.1002/aenm.201702232 SN - 1614-6832 SN - 1614-6840 VL - 8 IS - 12 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Heistermann, Maik A1 - Bogena, Heye A1 - Francke, Till A1 - Güntner, Andreas A1 - Jakobi, Jannis A1 - Rasche, Daniel A1 - Schrön, Martin A1 - Döpper, Veronika A1 - Fersch, Benjamin A1 - Groh, Jannis A1 - Patil, Amol A1 - Pütz, Thomas A1 - Reich, Marvin A1 - Zacharias, Steffen A1 - Zengerle, Carmen A1 - Oswald, Sascha T1 - Soil moisture observation in a forested headwater catchment: combining a dense cosmic-ray neutron sensor network with roving and hydrogravimetry at the TERENO site Wüstebach JF - Earth system science data : ESSD N2 - Cosmic-ray neutron sensing (CRNS) has become an effective method to measure soil moisture at a horizontal scale of hundreds of metres and a depth of decimetres. Recent studies proposed operating CRNS in a network with overlapping footprints in order to cover root-zone water dynamics at the small catchment scale and, at the same time, to represent spatial heterogeneity. In a joint field campaign from September to November 2020 (JFC-2020), five German research institutions deployed 15 CRNS sensors in the 0.4 km2 Wüstebach catchment (Eifel mountains, Germany). The catchment is dominantly forested (but includes a substantial fraction of open vegetation) and features a topographically distinct catchment boundary. In addition to the dense CRNS coverage, the campaign featured a unique combination of additional instruments and techniques: hydro-gravimetry (to detect water storage dynamics also below the root zone); ground-based and, for the first time, airborne CRNS roving; an extensive wireless soil sensor network, supplemented by manual measurements; and six weighable lysimeters. Together with comprehensive data from the long-term local research infrastructure, the published data set (available at https://doi.org/10.23728/b2share.756ca0485800474e9dc7f5949c63b872; Heistermann et al., 2022) will be a valuable asset in various research contexts: to advance the retrieval of landscape water storage from CRNS, wireless soil sensor networks, or hydrogravimetry; to identify scale-specific combinations of sensors and methods to represent soil moisture variability; to improve the understanding and simulation of land–atmosphere exchange as well as hydrological and hydrogeological processes at the hillslope and the catchment scale; and to support the retrieval of soil water content from airborne and spaceborne remote sensing platforms. Y1 - 2022 U6 - https://doi.org/10.5194/essd-14-2501-2022 SN - 1866-3516 SN - 1866-3508 VL - 14 IS - 5 SP - 2501 EP - 2519 PB - Copernicus CY - Katlenburg-Lindau ER - TY - GEN A1 - Zeuschner, Steffen Peer A1 - Parpiiev, Tymur A1 - Pezeril, Thomas A1 - Hillion, Arnaud A1 - Dumesnil, Karine A1 - Anane, Abdelmadjid A1 - Pudell, Jan-Etienne A1 - Willig, Lisa A1 - Rössle, Matthias A1 - Herzog, Marc A1 - Reppert, Alexander von A1 - Bargheer, Matias T1 - Tracking picosecond strain pulses in heterostructures that exhibit giant magnetostriction T2 - Postprints der Universität Potsdam : Mathematisch-naturwissenschaftliche Reihe N2 - We combine ultrafast X-ray diffraction (UXRD) and time-resolved Magneto-Optical Kerr Effect (MOKE) measurements to monitor the strain pulses in laser-excited TbFe2/Nb heterostructures. Spatial separation of the Nb detection layer from the laser excitation region allows for a background-free characterization of the laser-generated strain pulses. We clearly observe symmetric bipolar strain pulses if the excited TbFe2 surface terminates the sample and a decomposition of the strain wavepacket into an asymmetric bipolar and a unipolar pulse, if a SiO2 glass capping layer covers the excited TbFe2 layer. The inverse magnetostriction of the temporally separated unipolar strain pulses in this sample leads to a MOKE signal that linearly depends on the strain pulse amplitude measured through UXRD. Linear chain model simulations accurately predict the timing and shape of UXRD and MOKE signals that are caused by the strain reflections from multiple interfaces in the heterostructure. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 706 KW - Heterostructures KW - Magnetooptical effects KW - Metal oxides KW - Crystal lattices KW - Transition metals KW - Magnetism KW - Ultrafast X-ray diffraction KW - Lasers KW - Bragg peak KW - Phonons Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-428457 SN - 1866-8372 IS - 706 ER - TY - JOUR A1 - Zeuschner, Steffen Peer A1 - Parpiiev, Tymur A1 - Pezeril, Thomas A1 - Hillion, Arnaud A1 - Dumesnil, Karine A1 - Anane, Abdelmadjid A1 - Pudell, Jan-Etienne A1 - Willig, Lisa A1 - Rössle, Matthias A1 - Herzog, Marc A1 - Reppert, Alexander von A1 - Bargheer, Matias T1 - Tracking picosecond strain pulses in heterostructures that exhibit giant magnetostriction JF - Structural Dynamics N2 - We combine ultrafast X-ray diffraction (UXRD) and time-resolved Magneto-Optical Kerr Effect (MOKE) measurements to monitor the strain pulses in laser-excited TbFe2/Nb heterostructures. Spatial separation of the Nb detection layer from the laser excitation region allows for a background-free characterization of the laser-generated strain pulses. We clearly observe symmetric bipolar strain pulses if the excited TbFe2 surface terminates the sample and a decomposition of the strain wavepacket into an asymmetric bipolar and a unipolar pulse, if a SiO2 glass capping layer covers the excited TbFe2 layer. The inverse magnetostriction of the temporally separated unipolar strain pulses in this sample leads to a MOKE signal that linearly depends on the strain pulse amplitude measured through UXRD. Linear chain model simulations accurately predict the timing and shape of UXRD and MOKE signals that are caused by the strain reflections from multiple interfaces in the heterostructure. KW - Heterostructures KW - Magnetooptical effects KW - Metal oxides KW - Crystal lattices KW - Transition metals KW - Magnetism KW - Ultrafast X-ray diffraction KW - Lasers KW - Bragg peak KW - Phonons Y1 - 2019 U6 - https://doi.org/10.1063/1.5084140 SN - 2329-7778 VL - 6 IS - 2 PB - AIP Publishing LLC CY - Melville, NY ER -