TY - GEN A1 - Ślęzak, Jakub A1 - Metzler, Ralf A1 - Magdziarz, Marcin T1 - Superstatistical generalised Langevin equation BT - non-Gaussian viscoelastic anomalous diffusion N2 - Recent advances in single particle tracking and supercomputing techniques demonstrate the emergence of normal or anomalous, viscoelastic diffusion in conjunction with non-Gaussian distributions in soft, biological, and active matter systems. We here formulate a stochastic model based on a generalised Langevin equation in which non-Gaussian shapes of the probability density function and normal or anomalous diffusion have a common origin, namely a random parametrisation of the stochastic force. We perform a detailed analysis demonstrating how various types of parameter distributions for the memory kernel result in exponential, power law, or power-log law tails of the memory functions. The studied system is also shown to exhibit a further unusual property: the velocity has a Gaussian one point probability density but non-Gaussian joint distributions. This behaviour is reflected in the relaxation from a Gaussian to a non-Gaussian distribution observed for the position variable. We show that our theoretical results are in excellent agreement with stochastic simulations. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 413 KW - anomalous diffusion KW - generalised langevin equation KW - superstatistics KW - non-Gaussian diffusion Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-409315 ER - TY - JOUR A1 - Ślęzak, Jakub A1 - Metzler, Ralf A1 - Magdziarz, Marcin T1 - Superstatistical generalised Langevin equation BT - non-Gaussian viscoelastic anomalous diffusion JF - New Journal of Physics N2 - Recent advances in single particle tracking and supercomputing techniques demonstrate the emergence of normal or anomalous, viscoelastic diffusion in conjunction with non-Gaussian distributions in soft, biological, and active matter systems. We here formulate a stochastic model based on a generalised Langevin equation in which non-Gaussian shapes of the probability density function and normal or anomalous diffusion have a common origin, namely a random parametrisation of the stochastic force. We perform a detailed analysis demonstrating how various types of parameter distributions for the memory kernel result in exponential, power law, or power-log law tails of the memory functions. The studied system is also shown to exhibit a further unusual property: the velocity has a Gaussian one point probability density but non-Gaussian joint distributions. This behaviour is reflected in the relaxation from a Gaussian to a non-Gaussian distribution observed for the position variable. We show that our theoretical results are in excellent agreement with stochastic simulations. KW - anomalous diffusion KW - generalised langevin equation KW - superstatistics KW - non-Gaussian diffusion Y1 - 2018 U6 - https://doi.org/10.1088/1367-2630/aaa3d4 SN - 1367-2630 VL - 20 IS - 023026 SP - 1 EP - 25 PB - Deutsche Physikalische Gesellschaft / Institute of Physics CY - Bad Honnef und London ER - TY - JOUR A1 - Öztürk, Ugur A1 - Marwan, Norbert A1 - von Specht, Sebastian A1 - Korup, Oliver A1 - Jensen, J. T1 - A new centennial sea-level record for Antalya, Eastern Mediterranean JF - Journal of geophysical research-oceans N2 - Quantitative estimates of sea-level rise in the Mediterranean Basin become increasingly accurate thanks to detailed satellite monitoring. However, such measuring campaigns cover several years to decades, while longer-term sea-level records are rare for the Mediterranean. We used a data archeological approach to reanalyze monthly mean sea-level data of the Antalya-I (1935–1977) tide gauge to fill this gap. We checked the accuracy and reliability of these data before merging them with the more recent records of the Antalya-II (1985–2009) tide gauge, accounting for an eight-year hiatus. We obtain a composite time series of monthly and annual mean sea levels spanning some 75 years, providing the longest record for the eastern Mediterranean Basin, and thus an essential tool for studying the region's recent sea-level trends. We estimate a relative mean sea-level rise of 2.2 ± 0.5 mm/year between 1935 and 2008, with an annual variability (expressed here as the standard deviation of the residuals, σresiduals = 41.4 mm) above that at the closest tide gauges (e.g., Thessaloniki, Greece, σresiduals = 29.0 mm). Relative sea-level rise accelerated to 6.0 ± 1.5 mm/year at Antalya-II; we attribute roughly half of this rate (~3.6 mm/year) to tectonic crustal motion and anthropogenic land subsidence. Our study highlights the value of data archeology for recovering and integrating historic tide gauge data for long-term sea-level and climate studies. KW - sea level KW - tide gauge KW - data archeology KW - Mediterranean Sea Y1 - 2018 U6 - https://doi.org/10.1029/2018JC013906 SN - 2169-9275 SN - 2169-9291 VL - 123 IS - 7 SP - 4503 EP - 4517 PB - American Geophysical Union CY - Washington ER - TY - THES A1 - Öztürk, Ugur T1 - Learning more to predict landslides T1 - Ein verbessertes Wissen zur Prognose von Hangrutschungen N2 - Landslides are frequent natural hazards in rugged terrain, when the resisting frictional force of the surface of rupture yields to the gravitational force. These forces are functions of geological and morphological factors, such as angle of internal friction, local slope gradient or curvature, which remain static over hundreds of years; whereas more dynamic triggering events, such as rainfall and earthquakes, compromise the force balance by temporarily reducing resisting forces or adding transient loads. This thesis investigates landslide distribution and orientation due to landslide triggers (e.g. rainfall) at different scales (6-4∙10^5 km^2) and aims to link rainfall movement with the landslide distribution. It additionally explores the local impacts of the extreme rainstorms on landsliding and the role of precursory stability conditions that could be induced by an earlier trigger, such as an earthquake. Extreme rainfall is a common landslide trigger. Although several studies assessed rainfall intensity and duration to study the distribution of thus triggered landslides, only a few case studies quantified spatial rainfall patterns (i.e. orographic effect). Quantifying the regional trajectories of extreme rainfall could aid predicting landslide prone regions in Japan. To this end, I combined a non-linear correlation metric, namely event synchronization, and radial statistics to assess the general pattern of extreme rainfall tracks over distances of hundreds of kilometers using satellite based rainfall estimates. Results showed that, although the increase in rainfall intensity and duration positively correlates with landslide occurrence, the trajectories of typhoons and frontal storms were insufficient to explain landslide distribution in Japan. Extreme rainfall trajectories inclined northwestwards and were concentrated along some certain locations, such as coastlines of southern Japan, which was unnoticed in the landslide distribution of about 5000 rainfall-triggered landslides. These landslides seemed to respond to the mean annual rainfall rates. Above mentioned findings suggest further investigation on a more local scale to better understand the mechanistic response of landscape to extreme rainfall in terms of landslides. On May 2016 intense rainfall struck southern Germany triggering high waters and landslides. The highest damage was reported at the Braunsbach, which is located on the tributary-mouth fan formed by the Orlacher Bach. Orlacher Bach is a ~3 km long creek that drains a catchment of about ~6 km^2. I visited this catchment in June 2016 and mapped 48 landslides along the creek. Such high landslide activity was not reported in the nearby catchments within ~3300 km^2, despite similar rainfall intensity and duration based on weather radar estimates. My hypothesis was that several landslides were triggered by rainfall-triggered flash floods that undercut hillslope toes along the Orlacher Bach. I found that morphometric features such as slope and curvature play an important role in landslide distribution on this micro scale study site (<10 km^2). In addition, the high number of landslides along the Orlacher Bach could also be boosted by accumulated damages on hillslopes due karst weathering over longer time scales. Precursory damages on hillslopes could also be induced by past triggering events that effect landscape evolution, but this interaction is hard to assess independently from the latest trigger. For example, an earthquake might influence the evolution of a landscape decades long, besides its direct impacts, such as landslides that follow the earthquake. Here I studied the consequences of the 2016 Kumamoto Earthquake (MW 7.1) that triggered some 1500 landslides in an area of ~4000 km^2 in central Kyushu, Japan. Topography, i.e. local slope and curvature, both amplified and attenuated seismic waves, thus controlling the failure mechanism of those landslides (e.g. progressive). I found that topography fails in explaining the distribution and the preferred orientation of the landslides after the earthquake; instead the landslides were concentrated around the northeast of the rupture area and faced mostly normal to the rupture plane. This preferred location of the landslides was dominated mainly by the directivity effect of the strike-slip earthquake, which is the propagation of wave energy along the fault in the rupture direction; whereas amplitude variations of the seismic radiation altered the preferred orientation. I suspect that the earthquake directivity and the asymmetry of seismic radiation damaged hillslopes at those preferred locations increasing landslide susceptibility. Hence a future weak triggering event, e.g. scattered rainfall, could further trigger landslides at those damaged hillslopes. N2 - Hangrutschungen treten häufig in steilem Gelände auf, wenn die Erdanziehungskraft die Scherkräfte an der Oberfläche übersteigt. Diese Kräfte beinhalten geologische und geomorphologische Faktoren wie den Reibungswinkel oder die Neigung und Krümmung von Hängen, die über Jahrhunderte statisch bleiben können. Dynamische Ereignisse wie Regenfälle und Erdbeben können hingegen das Kräftegleichgewicht beeinträchtigen, indem sie Widerstandskräfte vorübergehend reduzieren oder Lasten temporär hinzufügen. Diese Arbeit untersucht die Verteilung und Orientierung von Hangrutschungen in Abhängigkeit von Auslösern (z.B. Niederschlag) auf verschiedenen Skalenebenen (6-4∙10^5 km^2) und verknüpft die Bewegung des Niederschlagssystems mit der Hangrutschungsverteilung. Zudem werden lokale Auswirkungen von extremen Gewittern auf Hangrutschungen untersucht, sowie vorausgehende Stabilitätsbedingungen, die durch ein früheres Ereignis, beispielsweise ein Erdbeben, verändert werden können. Extremer Niederschlag ist ein weithin bekannter Auslöser für Hangrutschungen. Obwohl mehrere Studien die Verteilung von Hangrutschungen mit der Niederschlagsintensität und -dauer verglichen haben, beachteten nur wenige Fallstudien das räumliche Bewegungsmuster des Niederschlags, i.e. den orographischen Effekt. Eine solche Quantifizierung könnte die Vorhersage von hangrutschungsgefährdete Regionen in Japan verbessern. Hierfür habe ich ein nicht-lineares Korrelationsmaß (event synchronization) auf regionale Sturmbahnen in Japan angewendet, um deren räumliche Verteilung durch satellitengestützen Regenschätzungen nachzuvollziehen. Die durchgeführten Untersuchungen zeigten, dass sich die Verteilung von Hangrutschungen nur unzureichend mit den Zugbahnen von Taifunen und Sturmtiefen erklären lässt. Die Stabilität von Hängen scheint mehr durch mittlere Jahresniederschlagsmengen beeinflusst zu werden. Erzielte Ergebnisse zeigen, dass weitere Untersuchungen auf lokaler Ebene nötig sind, um die unmittelbare Auswirkungen von Extremniederschlägen auf Hangstabilität und -rutschungen besser zu verstehen. Im Mai 2016 kam es in Süddeutschland zu einem heftigen Gewitter, das Hochwasser und Hangrutschungen ausgelöst hat. Der höchste Schaden wurde in Braunsbach, dessen Zentrum sich am Zufluss des Orlacher Bachs befindet, gemeldet. Der Orlacher Bach ist ~3 lang und hat ein Einzugsgebiet von etwa ~6 km^2. Ich habe dieses Einzugsgebiet im Juni 2016 besucht und 48 Hangrutschungen entlang des Baches kartiert. Ich vermutete, dass mehrere Hangrutschungen durch Sturzfluten ausgelöst wurden, welche die Hänge entlang des Orlacher Baches unterspülten. Ich stellte fest, dass morphometrische Merkmale wie die lokale Hangneigung und -krümmung eine wichtige Rolle bei der Hangrutschungsverteilung auf dieser Mikroskala spielen (<10 km^2). Darüber hinaus könnte die hohe Anzahl von Hangrutschungen am Orlacher Bach auch durch Karstverwitterung über längere Zeiträume verstärkt werden. Zahlreiche in der Vergangenheit liegende Ereignisse können die Stabilität eines Hanges beeinflussen. Der Einfluss solcher Ereignisse ist nur sehr schwer unabhängig voneinander abschätzbar. Beispielseise könnte ein Erdbeben die Entwicklung einer Landschaft über Jahrzehnte hin beeinflussen. Hier erforsche ich die Folgen des Kumamoto-Erdbebens 2016 (MW 7.1) das im Zentrum von Kyushu, Japan, ca. 1500 Hangrutschungen in einem Gebiet von ~4000 km^2 ausgelöst hat. Die Topographie (Hangneigung und -krümmung) verstärkte schwächte seismische Wellen gleichermaßen ab, wodurch der Auslösemechanismus dieser Hangrutschungen (z.B. progressiv) gesteuert wird. Ich konnte belegen, dass die Topographie die Verteilung und die bevorzugte Ausrichtung der Hangrutsche nach dem Erdbeben nicht erklären kann; stattdessen waren die Hangrutschungen um den Nordosten des Bruchgebiets herum konzentriert und standen meist senkrecht zur Bruchfläche. Diese bevorzugte Lage der Erdrutsche wurde hauptsächlich durch den Richtwirkungseffekt des Blattverschiebung-Erdbebens dominiert. Bei diesem handelt es sich um die Ausbreitung der Wellenenergie entlang des Bruches in Bruchrichtung, während Amplitudenvariationen der seismischen Strahlung die bevorzugte Orientierung ändern. Ich vermute, dass die Richtwirkung des Erdbebens und die Asymmetrie der seismischen Strahlung die Hangneigung an diesen bevorzugten Stellen schädigten und die Anfälligkeit für Hangrutschungen erhöhten. Daher könnte ein zukünftiges schwaches Ereignis wie z.B. ein unbedeutender Niederschlag an diesen beschädigten Hängen weitere Hangrutschungen auslösen. KW - landslides KW - complex networks KW - event synchronization KW - typhoons KW - Kumamoto earthquake KW - Braunsbach flash flood KW - Hangrutschungen KW - komplexes Netzwerk KW - Synchronisation von Ereignissen KW - Taifune KW - Kumamoto Erdbeben KW - Braunsbach Sturzflut Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426439 ER - TY - JOUR A1 - Özer, Aydan A1 - Scheffler, Christiane T1 - Affinity to host population stimulates physical growth in adult offspring of Turkish migrants in Germany JF - Journal of biological and clinical anthropology JF - Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Because of political conflicts and climate change, migration will be increased worldwide and integration in host societies is a challenge also for migrants. We hypothesize that migrants, who take up the challenge in a new social environment are taller than migrants who do not pose this challenge. We analyze by a questionnaire possible social, nutritional and ethnic influencing factors to body height (BH) of adult offspring of Turkish migrants (n = 82, 39 males) aged from 18 to 34 years (mean age 24.6 years). The results of multiple regression (downward selection) show that the more a male adult offspring of Turkish migrants feels like belonging to the Turkish culture, the smaller he is (95% CI, -3.79, -0.323). Further, the more a male adult offspring of Turkish migrants feels like belonging to the German culture, the taller he is (95% CI, -0.152, 1.738). We discussed it comparable to primates taking up their challenge in dominance, where as a result their body size increase is associated with higher IGF-1 level. IGF-1 is associated with emotional belonging and has a fundamental role in the regulation of metabolism and growth of the human body. With all pilot characteristics of our study results show that the successful challenge of integration in a new society is strongly associated with the emotional integration and identification in the sense of a personal sense of belonging to society. We discuss taller BH as a signal of social growth adjustment. In this sense, a secular trend of BH adaptation of migrants to hosts is a sign of integration. KW - height of Turkish migrants KW - social identification KW - strategic growth adjustments Y1 - 2018 U6 - https://doi.org/10.1127/anthranz/2018/0825 SN - 0003-5548 VL - 74 IS - 5 SP - 359 EP - 364 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Özcan, Orkan A1 - Bookhagen, Bodo A1 - Musaoglu, Nebiye T1 - Impact of the Ataturk Dam Lake on Agro-Meteorological Aspects of the Southeastern Anatolia Region, Turkey JF - Journal of the Indian Society of Remote Sensing N2 - In this study, the spatial and temporal impacts of the Ataturk Dam on agro-meteorological aspects of the Southeastern Anatolia region have been investigated. Change detection and environmental impacts due to water-reserve changes in Ataturk Dam Lake have been determined and evaluated using multi-temporal Landsat satellite imageries and meteorological datasets within a period of 1984-2011. These time series have been evaluated for three time periods. Dam construction period constitutes the first part of the study. Land cover/use changes especially on agricultural fields under the Ataturk Dam Lake and its vicinity have been identified between the periods of 1984-1992. The second period comprises the 10-year period after the completion of filling up the reservoir in 1992. At this period, Landsat and meteorological time-series analyses are examined to assess the impact of the Ataturk Dam Lake on selected irrigated agricultural areas. For the last 9-year period from 2002 to 2011, the relationships between seasonal water-reserve changes and irrigated plains under changing climatic factors primarily driving vegetation activity (monthly, seasonal, and annual fluctuations of rainfall rate, air temperature, humidity) on the watershed have been investigated using a 30-year meteorological time series. The results showed that approximately 368 km(2) of agricultural fields have been affected because of inundation due to the Ataturk Dam Lake. However, irrigated agricultural fields have been increased by 56.3% of the total area (1552 of 2756 km(2)) on Harran Plain within the period of 1984-2011. KW - Ataturk Dam Lake KW - Harran Plain KW - Landsat time-series KW - Tasseled Cap transformation KW - Disturbance index Y1 - 2018 U6 - https://doi.org/10.1007/s12524-017-0703-9 SN - 0255-660X SN - 0974-3006 VL - 46 IS - 3 SP - 471 EP - 481 PB - Springer CY - New York ER - TY - JOUR A1 - Öner, Ibrahim Halil A1 - Querebillo, Christine Joy A1 - David, Christin A1 - Gernert, Ulrich A1 - Walter, Carsten A1 - Driess, Matthias A1 - Leimkühler, Silke A1 - Ly, Khoa Hoang A1 - Weidinger, Inez M. T1 - High electromagnetic field enhancement of TiO2 nanotube electrodes JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition N2 - We present the fabrication of TiO2 nanotube electrodes with high biocompatibility and extraordinary spectroscopic properties. Intense surface-enhanced resonance Raman signals of the heme unit of the redox enzyme Cytochromeb(5) were observed upon covalent immobilization of the protein matrix on the TiO2 surface, revealing overall preserved structural integrity and redox behavior. The enhancement factor could be rationally controlled by varying the electrode annealing temperature, reaching a record maximum value of over 70 at 475 degrees C. For the first time, such high values are reported for non-directly surface-interacting probes, for which the involvement of charge-transfer processes in signal amplification can be excluded. The origin of the surface enhancement is exclusively attributed to enhanced localized electric fields resulting from the specific optical properties of the nanotubular geometry of the electrode. KW - electromagnetic field enhancement KW - photonic crystals KW - spectro-electrochemistry KW - surface-enhanced Raman spectroscopy KW - TiO2 nanotubes Y1 - 2018 U6 - https://doi.org/10.1002/anie.201802597 SN - 1433-7851 SN - 1521-3773 VL - 57 IS - 24 SP - 7225 EP - 7229 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Zöller, Gert A1 - Holschneider, Matthias T1 - Reply to “Comment on ‘The Maximum Possible and the Maximum Expected Earthquake Magnitude for Production‐Induced Earthquakes at the Gas Field in Groningen, The Netherlands’ by Gert Zöller and Matthias Holschneider” by Mathias Raschke T2 - Bulletin of the Seismological Society of America Y1 - 2018 U6 - https://doi.org/10.1785/0120170131 SN - 0037-1106 SN - 1943-3573 VL - 108 IS - 2 SP - 1029 EP - 1030 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Zöller, Gert T1 - A statistical model for earthquake recurrence based on the assimilation of paleoseismicity, historic seismicity, and instrumental seismicity JF - Journal of geophysical research : Solid earth N2 - Paleoearthquakes and historic earthquakes are the most important source of information for the estimation of long-term earthquake recurrence intervals in fault zones, because corresponding sequences cover more than one seismic cycle. However, these events are often rare, dating uncertainties are enormous, and missing or misinterpreted events lead to additional problems. In the present study, I assume that the time to the next major earthquake depends on the rate of small and intermediate events between the large ones in terms of a clock change model. Mathematically, this leads to a Brownian passage time distribution for recurrence intervals. I take advantage of an earlier finding that under certain assumptions the aperiodicity of this distribution can be related to the Gutenberg-Richter b value, which can be estimated easily from instrumental seismicity in the region under consideration. In this way, both parameters of the Brownian passage time distribution can be attributed with accessible seismological quantities. This allows to reduce the uncertainties in the estimation of the mean recurrence interval, especially for short paleoearthquake sequences and high dating errors. Using a Bayesian framework for parameter estimation results in a statistical model for earthquake recurrence intervals that assimilates in a simple way paleoearthquake sequences and instrumental data. I present illustrative case studies from Southern California and compare the method with the commonly used approach of exponentially distributed recurrence times based on a stationary Poisson process. KW - statistical seismology KW - paleoearthquakes KW - stochastic models KW - seismic hazard Y1 - 2018 U6 - https://doi.org/10.1029/2017JB015099 SN - 2169-9313 SN - 2169-9356 VL - 123 IS - 6 SP - 4906 EP - 4921 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Zwieback, Simon A1 - Kokelj, Steven V. A1 - Günther, Frank A1 - Boike, Julia A1 - Grosse, Guido A1 - Hajnsek, Irena T1 - Sub-seasonal thaw slump mass wasting is not consistently energy limited at the landscape scale JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - Predicting future thaw slump activity requires a sound understanding of the atmospheric drivers and geomorphic controls on mass wasting across a range of timescales. On sub-seasonal timescales, sparse measurements indicate that mass wasting at active slumps is often limited by the energy available for melting ground ice, but other factors such as rainfall or the formation of an insulating veneer may also be relevant. To study the sub-seasonal drivers, we derive topographic changes from single-pass radar interferometric data acquired by the TanDEM-X satellites. The estimated elevation changes at 12m resolution complement the commonly observed planimetric retreat rates by providing information on volume losses. Their high vertical precision (around 30 cm), frequent observations (11 days) and large coverage (5000 km(2)) allow us to track mass wasting as drivers such as the available energy change during the summer of 2015 in two study regions. We find that thaw slumps in the Tuktoyaktuk coastlands, Canada, are not energy limited in June, as they undergo limited mass wasting (height loss of around 0 cm day 1) despite the ample available energy, suggesting the widespread presence of early season insulating snow or debris veneer. Later in summer, height losses generally increase (around 3 cm day 1), but they do so in distinct ways. For many slumps, mass wasting tracks the available energy, a temporal pattern that is also observed at coastal yedoma cliffs on the Bykovsky Peninsula, Russia. However, the other two common temporal trajectories are asynchronous with the available energy, as they track strong precipitation events or show a sudden speed-up in late August respectively. The observed temporal patterns are poorly related to slump characteristics like the headwall height. The contrasting temporal behaviour of nearby thaw slumps highlights the importance of complex local and temporally varying controls on mass wasting. Y1 - 2018 U6 - https://doi.org/10.5194/tc-12-549-2018 SN - 1994-0416 SN - 1994-0424 VL - 12 IS - 2 SP - 549 EP - 564 PB - Copernicus CY - Göttingen ER - TY - GEN A1 - Zwieback, Simon A1 - Kokelj, Steven V. A1 - Günther, Frank A1 - Boike, Julia A1 - Grosse, Guido A1 - Hajnsek, Irena T1 - Sub-seasonal thaw slump mass wasting is not consistently energy limited at the landscape scale T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Predicting future thaw slump activity requires a sound understanding of the atmospheric drivers and geomorphic controls on mass wasting across a range of timescales. On sub-seasonal timescales, sparse measurements indicate that mass wasting at active slumps is often limited by the energy available for melting ground ice, but other factors such as rainfall or the formation of an insulating veneer may also be relevant. To study the sub-seasonal drivers, we derive topographic changes from single-pass radar interferometric data acquired by the TanDEM-X satellites. The estimated elevation changes at 12m resolution complement the commonly observed planimetric retreat rates by providing information on volume losses. Their high vertical precision (around 30 cm), frequent observations (11 days) and large coverage (5000 km(2)) allow us to track mass wasting as drivers such as the available energy change during the summer of 2015 in two study regions. We find that thaw slumps in the Tuktoyaktuk coastlands, Canada, are not energy limited in June, as they undergo limited mass wasting (height loss of around 0 cm day 1) despite the ample available energy, suggesting the widespread presence of early season insulating snow or debris veneer. Later in summer, height losses generally increase (around 3 cm day 1), but they do so in distinct ways. For many slumps, mass wasting tracks the available energy, a temporal pattern that is also observed at coastal yedoma cliffs on the Bykovsky Peninsula, Russia. However, the other two common temporal trajectories are asynchronous with the available energy, as they track strong precipitation events or show a sudden speed-up in late August respectively. The observed temporal patterns are poorly related to slump characteristics like the headwall height. The contrasting temporal behaviour of nearby thaw slumps highlights the importance of complex local and temporally varying controls on mass wasting. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 926 KW - ground-ice KW - Tandem-X KW - Northeast Siberia KW - thermal regime KW - Peel Plateau KW - permafrost KW - erosion KW - Island KW - delta KW - yedoma Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-445688 SN - 1866-8372 IS - 926 SP - 549 EP - 564 ER - TY - JOUR A1 - Zwickel, Theresa A1 - Kahl, Sandra M. A1 - Rychlik, Michael A1 - Müller, Marina E. H. T1 - Chemotaxonomy of Mycotoxigenic Small-Spored Alternaria Fungi BT - Do Multitoxin Mixtures Act as an Indicator for Species Differentiation? JF - Frontiers in microbiology N2 - Necrotrophic as well as saprophytic small-spored Altemaria (A.) species are annually responsible for major losses of agricultural products, such as cereal crops, associated with the contamination of food and feedstuff with potential health-endangering Altemaria toxins. Knowledge of the metabolic capabilities of different species-groups to form mycotoxins is of importance for a reliable risk assessment. 93 Altemaria strains belonging to the four species groups Alternaria tenuissima, A. arborescens, A. altemata, and A. infectoria were isolated from winter wheat kernels harvested from fields in Germany and Russia and incubated under equal conditions. Chemical analysis by means of an HPLC-MS/MS multi-Alternaria-toxin-method showed that 95% of all strains were able to form at least one of the targeted 17 non-host specific Altemaria toxins. Simultaneous production of up to 15 (modified) Altemaria toxins by members of the A. tenuissima, A. arborescens, A. altemata species-groups and up to seven toxins by A. infectoria strains was demonstrated. Overall tenuazonic acid was the most extensively formed mycotoxin followed by alternariol and alternariol mono methylether, whereas altertoxin I was the most frequently detected toxin. Sulfoconjugated modifications of alternariol, alternariol mono methylether, altenuisol and altenuene were frequently determined. Unknown perylene quinone derivatives were additionally detected. Strains of the species-group A. infectoria could be segregated from strains of the other three species-groups due to significantly lower toxin levels and the specific production of infectopyrone. Apart from infectopyrone, alterperylenol was also frequently produced by 95% of the A. infectoria strains. Neither by the concentration nor by the composition of the targeted Altemaria toxins a differentiation between the species-groups A. altemata, A. tenuissima and A. arborescens was possible. KW - small-spored Alternaria fungi KW - Alternaria species-groups KW - Alternaria mycotoxins KW - chemotaxonomy KW - secondary metabolite profiling KW - LC-MS/MS KW - wheat KW - perylene quinone derivatives Y1 - 2018 U6 - https://doi.org/10.3389/fmicb.2018.01368 SN - 1664-302X VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Zwickel, Theresa A1 - Kahl, Sandra M. A1 - Rychlik, Michael A1 - Müller, Marina E. H. T1 - Chemotaxonomy of mycotoxigenic small-spored Alternaria fungi BT - do multitoxin mixtures act as an indicator for species differentiation? T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Necrotrophic as well as saprophytic small-spored Altemaria (A.) species are annually responsible for major losses of agricultural products, such as cereal crops, associated with the contamination of food and feedstuff with potential health-endangering Altemaria toxins. Knowledge of the metabolic capabilities of different species-groups to form mycotoxins is of importance for a reliable risk assessment. 93 Altemaria strains belonging to the four species groups Alternaria tenuissima, A. arborescens, A. altemata, and A. infectoria were isolated from winter wheat kernels harvested from fields in Germany and Russia and incubated under equal conditions. Chemical analysis by means of an HPLC-MS/MS multi-Alternaria-toxin-method showed that 95% of all strains were able to form at least one of the targeted 17 non-host specific Altemaria toxins. Simultaneous production of up to 15 (modified) Altemaria toxins by members of the A. tenuissima, A. arborescens, A. altemata species-groups and up to seven toxins by A. infectoria strains was demonstrated. Overall tenuazonic acid was the most extensively formed mycotoxin followed by alternariol and alternariol mono methylether, whereas altertoxin I was the most frequently detected toxin. Sulfoconjugated modifications of alternariol, alternariol mono methylether, altenuisol and altenuene were frequently determined. Unknown perylene quinone derivatives were additionally detected. Strains of the species-group A. infectoria could be segregated from strains of the other three species-groups due to significantly lower toxin levels and the specific production of infectopyrone. Apart from infectopyrone, alterperylenol was also frequently produced by 95% of the A. infectoria strains. Neither by the concentration nor by the composition of the targeted Altemaria toxins a differentiation between the species-groups A. altemata, A. tenuissima and A. arborescens was possible. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 696 KW - small-spored Alternaria fungi KW - Alternaria species-groups KW - Alternaria mycotoxins KW - chemotaxonomy KW - secondary metabolite profiling KW - LC-MS/MS KW - wheat KW - perylene quinone derivatives Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426623 SN - 1866-8372 IS - 696 ER - TY - JOUR A1 - Zurell, Damaris A1 - von Wehrden, Henrik A1 - Rotics, Shay A1 - Kaatz, Michael A1 - Gross, Helge A1 - Schlag, Lena A1 - Schäfer, Merlin A1 - Sapir, Nir A1 - Turjeman, Sondra A1 - Wikelski, Martin A1 - Nathan, Ran A1 - Jeltsch, Florian T1 - Home range size and resource use of breeding and non-breeding white storks along a land use gradient JF - Frontiers in Ecology and Evolution N2 - Biotelemetry is increasingly used to study animal movement at high spatial and temporal resolution and guide conservation and resource management. Yet, limited sample sizes and variation in space and habitat use across regions and life stages may compromise robustness of behavioral analyses and subsequent conservation plans. Here, we assessed variation in (i) home range sizes, (ii) home range selection, and (iii) fine-scale resource selection of white storks across breeding status and regions and test model transferability. Three study areas were chosen within the Central German breeding grounds ranging from agricultural to fluvial and marshland. We monitored GPS-locations of 62 adult white storks equipped with solar-charged GPS/3D-acceleration (ACC) transmitters in 2013-2014. Home range sizes were estimated using minimum convex polygons. Generalized linear mixed models were used to assess home range selection and fine-scale resource selection by relating the home ranges and foraging sites to Corine habitat variables and normalized difference vegetation index in a presence/pseudo-absence design. We found strong variation in home range sizes across breeding stages with significantly larger home ranges in non-breeding compared to breeding white storks, but no variation between regions. Home range selection models had high explanatory power and well predicted overall density of Central German white stork breeding pairs. Also, they showed good transferability across regions and breeding status although variable importance varied considerably. Fine-scale resource selection models showed low explanatory power. Resource preferences differed both across breeding status and across regions, and model transferability was poor. Our results indicate that habitat selection of wild animals may vary considerably within and between populations, and is highly scale dependent. Thereby, home range scale analyses show higher robustness whereas fine-scale resource selection is not easily predictable and not transferable across life stages and regions. Such variation may compromise management decisions when based on data of limited sample size or limited regional coverage. We thus recommend home range scale analyses and sampling designs that cover diverse regional landscapes and ensure robust estimates of habitat suitability to conserve wild animal populations. KW - 3D-acceleration sensor KW - biotelemetry KW - Ciconia ciconia KW - home range selection KW - resource selection Y1 - 2018 U6 - https://doi.org/10.3389/fevo.2018.00079 SN - 2296-701X VL - 6 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Zuba, Anna A1 - Warschburger, Petra T1 - Weight bias internalization across weight categories among school-aged children BT - validation of the weight bias internalization scale for children JF - Body image : an international journal of research N2 - Anti-fat bias is widespread and is linked to the internalization of weight bias and psychosocial problems. The purpose of this study was to examine the internalization of weight bias among children across weight categories and to evaluate the psychometric properties of the Weight Bias Internalization Scale for Children (WBIS-C). Data were collected from 1484 primary school children and their parents. WBIS-C demonstrated good internal consistency (alpha = .86) after exclusion of Item 1. The unitary factor structure was supported using exploratory and confirmatory factor analyses (factorial validity). Girls and overweight children reported higher WBIS-C scores in comparison to boys and non-overweight peers (known-groups validity). Convergent validity was shown by significant correlations with psychosocial problems. Internalization of weight bias explained additional variance in different indicators of psychosocial well-being. The results suggest that the WBIS-C is a psychometrically sound and informative tool to assess weight bias internalization among children. KW - Internalization of weight bias KW - Weight stigma KW - Psychological functioning KW - Psychometric properties KW - Children Y1 - 2018 U6 - https://doi.org/10.1016/j.bodyim.2018.02.008 SN - 1740-1445 SN - 1873-6807 VL - 25 SP - 56 EP - 65 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Zuba, Anna T1 - The role of weight stigma and weight bias internalization in psychological functioning among school-aged children Y1 - 2018 ER - TY - RPRT A1 - Zivkovic, Velimir T1 - International Rule of Law Through International Investment Law BT - Strengths, Challenges and Opportunities T2 - KFG Working Paper Series N2 - In challenging times for international law, there might be a heightened need for both analysis and prescription. The international rule of law as a connecting thread that goes through the global legal order is a particularly salient topic. By providing a working understanding of the content and contexts of the international rule of law, and by taking the regime of international investment law as a case study, this paper argues that assessing 'rise' or 'decline' motions in this sphere warrants a nuanced approach that should recognise parallel positive and negative developments. Whilst prominent procedural and substantive aspects of international investment law strongly align with the international rule of law requirements, numerous challenges threaten the future existence of the regime and appeal of international rule of law more broadly. At the same time, opportunities exist to adapt the substantive decision-making processes in investor-State disputes so to pursue parallel goals of enhancing rule of law at both international and national levels. Through recognising the specificities of interaction between international and national sphere, arbitrators can further reinvigorate the legitimacy of international rule of law through international investment law - benefitting thus the future of both. T3 - KFG Working Paper Series - 16 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-422181 SN - 2509-3770 SN - 2509-3762 IS - 16 ER - TY - JOUR A1 - Zivanovic, Vesna A1 - Kochovski, Zdravko A1 - Arenz, Christoph A1 - Lu, Yan A1 - Kneipp, Janina T1 - SERS and Cryo-EM Directly Reveal Different Liposome Structures during Interaction with Gold Nanoparticles JF - The journal of physical chemistry letters N2 - The combination of gold nanoparticles with liposomes is important for nano- and biotechnology. Here, we present direct, label-free characterization of liposome structure and composition at the site of its interaction with citrate-stabilized gold nanoparticles by surface-enhanced Raman scattering (SERS) and cryogenic electron microscopy (cryo-EM). Evidenced by the vibrational spectra and cryo-EM, the gold nanoparticles destroy the bilayer structure of interacting liposomes in the presence of a high amount of citrate, while at lower citrate concentration the nanoparticles interact with the surface of the intact liposomes. The spectra of phosphatidylcholine and phosphatidylcholine/sphingomyelin liposomes show that at the site of interaction the lipid chains are in the gel phase. The SERS spectra indicate that cholesterol has strong effects on the contacts of the vesicles with the nanoparticles. By combining cryo-EM and SERS, the structure and properties of lipid nanoparticle composites could be tailored for the development of drug delivery systems. Y1 - 2018 U6 - https://doi.org/10.1021/acs.jpclett.8b03191 SN - 1948-7185 VL - 9 IS - 23 SP - 6767 EP - 6772 PB - American Chemical Society CY - Washington ER - TY - GEN A1 - Zitzmann, Jana A1 - Warschburger, Petra T1 - Psychometric properties of figure rating scales in children BT - the impact of figure ordering T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - This study examined psychometric properties of figure rating scales, particularly the effects of ascending silhouette ordering, in 153 children, 9 to 13 years old. Two versions of Collins’s (1991) figural rating scale were presented: the original scale (figures arranged ascendingly) and a modified version (randomized figure ordering. Ratings of current and ideal figure were elicited and body dissatisfaction was calculated. All children were randomly assigned to one of two subgroups and completed both scale versions in a different sequence. There were no significant differences in figure selection and body dissatisfaction between the two figure orderings. Regarding the selection of the current figure, results showed that girls are more affected by the silhouette ordering than boys. Our results suggest that figure rating scales are both valid and reliable, whereby correlation coefficients reveal greater stability for ideal figure selections and body dissatisfaction ratings when using the scale with ascending figure ordering. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 487 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-416871 SN - 1866-8364 IS - 487 ER - TY - JOUR A1 - Zimmermann, Matthias A1 - Scholz, Jana A1 - Eckardt, Barbara A1 - Kampe, Heike A1 - Görlich, Petra A1 - Horn-Conrad, Antje T1 - Portal Wissen = Language BT - The Research Magazine of the University of Potsdam N2 - Language is perhaps the most universal tool of human beings. It enables us to express ourselves, to communicate and understand, to help and get help, to create and share togetherness. However, that does not completely capture the value of language. “Language belongs to the character of man,” said the English philosopher Sir Francis Bacon. If you believe the poet Johann Gottfried von Herder, a human is “only a human through language”. Ultimately, this means that we live in our world not with, but in, language. We not only describe our reality by means of language, but language is the device through which we open up the world in the first place. It is always there and shapes and influences us and the way we perceive, analyze, describe and ultimately determine everything around us. Since it is so deeply connected with human nature, it is hardly surprising that our language has always been in the center of academic research – and not only in those fields that bear the name linguistics. Philosophy and media studies, neurology and psychology, computer science and semiotics – all of them are based on linguistic structures and their premises and possibilities. Since July 2017, a scientific network at the University of Potsdam has been working on exactly this interface: the Collaborative Research Center “Limits of Variability in Language” (SFB 1287), funded by the German Research Foundation (DFG). Linguists, computer scientists, psychologists, and neurologists examine where language is or is not flexible. They hope to find out more about individual languages and their connections. In this issue of Portal Wissen, we asked SFB spokeswoman Isabell Wartenburger and deputy spokesman Malte Zimmermann to talk about language, its variability and limits, and how they investigate these aspects. We also look over the shoulders of two researchers who are working on sub-projects: Germanist Heike Wiese and her team examine whether the pandemonium of the many different languages spoken at a weekly market in Berlin is creating a new language with its own rules. Linguist Doreen Georgi embarks on a typological journey around the world comparing about 30 languages to find out if they have common limits. We also want to introduce other research projects at the University of Potsdam and the people behind them. We talk to biologists about biodiversity and ecological dynamics, and the founders of the startup “visionYOU” explain how entrepreneurship can be combined with social responsibility. Other discussions center round the effective production of antibodies and the question of whether the continued use of smartphones will eventually make us speechless. But do not worry: we did not run out of words – the magazine is full of them! Enjoy your reading! The Editors T3 - Portal Wissen: The research magazine of the University of Potsdam [Englische Ausgabe] - 01/2018 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-441666 SN - 2198-9974 IS - 01/2018 ER - TY - JOUR A1 - Zimmermann, Marc A1 - John, Daniela A1 - Grigoriev, Dmitry A1 - Puretskiy, Nikolay A1 - Böker, Alexander T1 - From 2D to 3D patches on multifunctional particles BT - how microcontact printing creates a new dimension of functionality JF - Soft matter N2 - A straightforward approach for the precise multifunctional surface modification of particles with three-dimensional patches using microcontact printing is presented. By comparison to previous works it was possible to not only control the diameter, but also to finely tune the thickness of the deposited layer, opening up the way for three-dimensional structures and orthogonal multifunctionality. The use of PEI as polymeric ink, PDMS stamps for microcontact printing on silica particles and the influence of different solvents during particle release on the creation of functional particles with three-dimensional patches are described. Finally, by introducing fluorescent properties by incorporation of quantum dots into patches and by particle self-assembly via avidin-biotin coupling, the versatility of this novel modification method is demonstrated. Y1 - 2018 U6 - https://doi.org/10.1039/c8sm00163d SN - 1744-683X SN - 1744-6848 VL - 14 IS - 12 SP - 2301 EP - 2309 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Zimmermann, Marc A1 - Grigoriev, Dmitry A1 - Puretskiy, Nikolay A1 - Böker, Alexander T1 - Characteristics of microcontact printing with polyelectrolyte ink for the precise preparation of patches on silica particles JF - RSC Advances N2 - This publication demonstrates the abilities of a precise and straightforward microcontact printing approach for the preparation of patchy silica particles. In a broad particle size range, it is possible to finely tune the number and parameters of three-dimensional patches like diameter and thickness using only polyethyleneimine ink, poly(dimethoxysilane) as stamp material and a suitable release solvent. Y1 - 2018 U6 - https://doi.org/10.1039/c8ra07955b SN - 2046-2069 VL - 8 IS - 69 SP - 39241 EP - 39247 PB - Royal Society of Chemistry CY - Cambridge ER - TY - THES A1 - Zimmermann, Marc T1 - Multifunctional patchy silica particles via microcontact printing T1 - Multifunktionale Patchy Silika Partikel mithilfe des Mikrokontaktdruckverfahrens N2 - This research addressed the question, if it is possible to simplify current microcontact printing systems for the production of anisotropic building blocks or patchy particles, by using common chemicals while still maintaining reproducibility, high precision and tunability of the Janus-balance Chapter 2 introduced the microcontact printing materials as well as their defined electrostatic interactions. In particular polydimethylsiloxane stamps, silica particles and high molecular weight polyethylenimine ink were mainly used in this research. All of these components are commercially available in large quantities and affordable, which gives this approach a huge potential for further up-scaling developments. The benefits of polymeric over molecular inks was described including its flexible influence on the printing pressure. With this alteration of the µCP concept, a new method of solvent assisted particle release mechanism enabled the switch from two-dimensional surface modification to three-dimensional structure printing on colloidal silica particles, without changing printing parameters or starting materials. This effect opened the way to use the internal volume of the achieved patches for incorporation of nano additives, introducing additional physical properties into the patches without alteration of the surface chemistry. The success of this system and its achievable range was further investigated in chapter 3 by giving detailed information about patch geometry parameters including diameter, thickness and yield. For this purpose, silica particles in a size range between 1µm and 5µm were printed with different ink concentrations to change the Janus-balance of these single patched particles. A necessary intermediate step, consisting of air-plasma treatment, for the production of trivalent particles using "sandwich" printing was discovered and comparative studies concerning the patch geometry of single and double patched particles were conducted. Additionally, the usage of structured PDMS stamps during printing was described. These results demonstrate the excellent precision of this approach and opens the pathway for even greater accuracy as further parameters can be finely tuned and investigated, e.g. humidity and temperature during stamp loading. The performance of these synthesized anisotropic colloids was further investigated in chapter 4, starting with behaviour studies in alcoholic and aqueous dispersions. Here, the stability of the applied patches was studied in a broad pH range, discovering a release mechanism by disabling the electrostatic bonding between particle surface and polyelectrolyte ink. Furthermore, the absence of strong attractive forces between divalent particles in water was investigated using XPS measurements. These results lead to the conclusion that the transfer of small PDMS oligomers onto the patch surface is shielding charges, preventing colloidal agglomeration. However, based on this knowledge, further patch modifications for particle self-assembly were introduced including physical approaches using magnetic nano additives, chemical patch functionalization with avidin-biotin or the light responsive cyclodextrin-arylazopyrazoles coupling as well as particle surface modification for the synthesis of highly amphiphilic colloids. The successful coupling, its efficiency, stability and behaviour in different solvents were evaluated to find a suitable coupling system for future assembly experiments. Based on these results the possibility of more sophisticated structures by colloidal self-assembly is given. Certain findings needed further analysis to understand their underlying mechanics, including the relatively broad patch diameter distribution and the decreasing patch thickness for smaller silica particles. Mathematical assumptions for both effects are introduced in chapter 5. First, they demonstrate the connection between the naturally occurring particle size distribution and the broadening of the patch diameter, indicating an even higher precision for this µCP approach. Second, explaining the increase of contact area between particle and ink surface due to higher particle packaging, leading to a decrease in printing pressure for smaller particles. These calculations ultimately lead to the development of a new mechanical microcontact printing approach, using centrifugal forces for high pressure control and excellent parallel alignment of printing substrates. First results with this device and the comparison with previously conducted by-hand experiments conclude this research. It furthermore displays the advantages of such a device for future applications using a mechanical printing approach, especially for accessing even smaller nano particles with great precision and excellent yield. In conclusion, this work demonstrates the successful adjustment of the µCP approach using commercially available and affordable silica particles and polyelectrolytes for high flexibility, reduced costs and higher scale-up value. Furthermore, its was possible to increase the modification potential by introducing three-dimensional patches for additional functionalization volume. While keeping a high colloidal stability, different coupling systems showed the self-assembly capabilities of this toolbox for anisotropic particles. N2 - Diese Forschungsarbeit befasste sich mit der Frage, ob es möglich ist, bekannte Mikrokontaktdruckverfahren, zur Herstellung von anisotropen Bausteinen (Patchy Partikel), weiter zu vereinfachen. Dabei sollten gängige Chemikalien verwendet werden ohne einen Verlust in Reproduzierbarkeit, hoher Präzision und Feineinstellung der Janus-Balance zu erleiden. In Kapitel 2 wurden die verwendeten Mikrokontaktdruckmaterialien sowie deren elektrostatische Wechselwirkungen vorgestellt. Insbesondere handelte es sich dabei um Polydimethylsiloxan Stempel, Silikapartikel und hoch molekulare Polyethylenimin Tinte. All diese Produkte sind kommerziel in großen und bezahlbaren Mengen erhältlich. Nicht nur die Vorteile von polymeren Tinten im Gegensatz zu molekularen Tinten wurde beschrieben, sondern auch die hohe Flexibilität dieses Verfahrens bezüglich der verwendeten Druckkraft. Mit dieser Anpassung des Mikrokontaktdrucks, wurde eine neue Methode der Lösungsmittel unterstützten Partikelablösung ermöglicht, mit deren Hilfe ein einfaches Schalten zwischen zwei dimensionaler Oberflächenfunktionalisierung und drei dimensionalem Strukturdrucks möglich war, ohne Druckparameter oder Startchemikalien zu verändern. Dadurch konnte neu erschaffenes internes Volumen verwendet werden um Nanoadditive einzuführen und so zusätzliche physikalische Eigenschaften zu integrieren, ohne die Oberflächenchemie der Patches verändert wurde. Der Erfolg dieses Systems und seine erreichbaren Grenzen wurde gründlichst in Kapitel 3 erforscht, indem detaillierte Geometrieparameter der Patches einschließlich Durchmesser, Dicke und Ausbeute, erworben wurden. Hierfür wurden Silikapartikel in einem Größenbereich von 1µm bis 5µm mit unterschiedlichen Tintenkonzentrationen bedruckt, um Veränderungen erforschen zu können. Ein notwendiger Luftplasma Ätzschritt für die Produktion von trivalenten Partikeln, mit Hilfe des sogenannten ,,Sandwich‘‘-Drucks, wurde erläutert und vergleichende Untersuchen von einfach und zweifach modifizierten Bausteinen wurden durchgeführt. Zusätzlich dazu, wurde die Verwendung von strukturierten Stempel beschrieben. Die Ergebnisse verdeutlichen die exzellente Genauigkeit dieser Methode und öffnet den Weg um eine hoch höhere Präzision zu erreichen da weitere Parametere genau eingestellt und untersucht werden können, z.B. Luftfeuchtigkeit und Temperature während der Stempelbeladung. Die Performance der herstellten anisotropen Partikel wurde in Kapitel 4 mit Verhaltensstudien in alkoholischen und wässrigen Dispersionen getestet. Dabei wurde die Stabilität der Oberflächenfunktionalisierungen in einem breiten pH Bereich untersucht. Dadurch wurde ein Ablösungsmechanismus bei sehr hohen bzw. niedrigen pH-Werten entdeckt, der zur Deaktivierung elektrostatischer Wechselwirkungen zwischen Partikeloberfläche und Polyelektrolyte Tinte führte. Desweitern wurden die Abwesenheit starker Wechselwirkung der divalenten Partikel in Wasser mit Hilfe von XPS untersucht. Das Resultat zeigte, dass der Transfer kleinster PDMS Oligomere auf die Patchoberfläche zu einer Ladungsabschirmung führte. Dadurch konnte Agglomeration verhindert werden. Aufgrund dieser Ergebnisse wurden weitere Modifikationen für Partikelassemblierung durchgeführt. Hierfür wurde die Einführung von magnetischen Nanoadditiven, die Funktionalisierung mit Avidin-Biotin sowie dem Lichtschaltbaren Cyclodextrin-Arylazopyrazol Komplexen und die Partikeloberflächenfunktionalisierung zur Herstellung amphiphiler Teilchen untersucht. Die Effizienz der Kopplung, deren Stabilität sowie das Verhalten in unterschiedlichen Lösungsmittel wurde beschrieben. Basierend auf diesen Ergebnissen können noch anspruchsvollere Strukturen durch kolloidale Selbstassemblierung erzeugt werden. Einige Ergebnisse dieser Arbeit benötigten zusätzlicher Analyse um die zugrundeliegenden Mechaniken verstehen zu können. Dazu gehörte die relative hohe Streuung des Durchmessers für unterschiedliche Partikelsysteme, sowie das Ausdünnen des Patches mit kleineren Silikapartikeln. Mathematische Modelle in Kapitel 5 beschreiben beide Effekte. Dadurch war es möglich einen Zusammenhang zwischen der natürlichen Partikelgrößenverteilung sowie der Verbreitung des Patchdurchmessers festzustellen. Des Weiteren konnte eine Verkleinerung der Druckkraft durch eine Erhöhung der Packungsdichte für kleine Partikel beschrieben werden, wodurch eine Erklärung der Ausdünnung möglich war. All diese Berechnung führten schlussendlich zur Entwicklung eines neuen mechanischen Mikrokontaktdruckverfahrens, welches mit Hilfe von Zentrifugalkräften eine hohe Druckkontrolle und eine exzellente parallele Ausrichtung zwischen den Substraten ermöglicht. Erste Ergebnisse, sowie deren Vergleich mit bisher erhaltenen Resultaten schließen diese Forschung ab. Des Weiteren zeigt es die Vorteile einer solchen Vorrichtung für kommende Applikationen, besonders um noch kleinere Nanopartikel mit einer hohen Präzision modifizieren zu können. Zusammenfassend ist zu sagen, dass diese Forschung die erfolgreiche Anpassung des Mikrokontaktdruckverfahrens mit kommerziell erhältlichen und bezahlbaren Silikapartikeln und Polyelektrolyten demonstriert, um hohe Flexibilität, reduzierte Kosten und ein erweitertes Skalierungspotential zu bieten. Zusätzlich ist es gelungen, die Funktionalisierungsdichte zu erhöhen, indem drei dimensionaler Strukturdruck bisher ungenutztes Volumen schaffen konnte. Während eine hohe kolloidale Stabilität erhalten blieb, ist es gelungen unterschiedliche Kopplungssysteme zu nutzen, um das Selbstorganisationspotential dieser Toolbox für anisotrope Partikel aufzuzeigen. KW - patchy particles KW - microcontact printing KW - silica particles KW - anisotropic colloids KW - polyelectrolytes KW - Patchy Partikel KW - Mikrokontaktdruck KW - Silika Partikel KW - Anisotrope Kolloide KW - Polyelektrolyte Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427731 ER - TY - JOUR A1 - Zimmermann, Malte T1 - Wird Schon Stimmen! BT - A Degree Operator Analysis of Schon JF - Journal of semantics N2 - The article puts forward a novel analysis of the German modal particle schon as a modal degree operator over propositional content. The proposed analysis offers a uniform perspective on the semantics of modal schon and its aspectual counterpart meaning ‘already’: Both particles are analyzed as denoting a degree operator, expressing a scale-based comparison over relevant alternatives. The alternatives are determined by focus in the case of aspectual schon (Krifka 2000), but are restricted to the polar alternatives p and ¬p in the case of modal schon. Semantically, modal schon introduces a presupposition to the effect that the circumstantial conversational background contains more factual evidence in favor of p than in favor of ¬p⁠, thereby making modal schon the not at-issue counterpart of the overt comparative form eher ‘rather’ (Herburger & Rubinstein 2014). The analysis incorporates basic insights from earlier analyses of modal schon in a novel way, and it also offers new insights as to the underlying workings of modality in natural language as involving propositions rather than possible worlds (Kratzer 1977, 2012). Y1 - 2018 U6 - https://doi.org/10.1093/jos/ffy010 SN - 0167-5133 SN - 1477-4593 VL - 35 IS - 4 SP - 687 EP - 739 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Zimmermann, Andreas A1 - Boos, Felix T1 - Bringing States to Justice for Crimes against Humanity BT - The Compromissory Clause in the International Law Commission Draft Convention on Crimes against Humanity JF - Journal of international criminal justice N2 - Draft Article 15 of the International Law Commission’s project on crimes against humanity — dealing with the settlement of disputes arising from a proposed convention — attempts to strike a balance between state autonomy and robust judicial supervision. It largely follows Article 22 of the Convention on the Elimination of All Forms of Racial Discrimination, which renders the jurisdiction of the International Court of Justice (ICJ) conditional upon prior negotiations. Hence, the substance of the clause can be interpreted in light of the recent case law of the ICJ, especially in the case Georgia v. Russia. In addition, this contribution discusses several issues regarding the scope ratione temporis of the compromissory clause. It advances several proposals to improve the current draft, addressing its relationship with state responsibility — an explicit reference to which is currently missing — as well as the relationship between the ICJ and a possible treaty body. It also proposes to recalibrate the interplay of the requirement of prior negotiations with, respectively, the possibility of seizing a future treaty body and the indication of provisional measures by the ICJ. Y1 - 2018 U6 - https://doi.org/10.1093/jicj/mqy053 SN - 1478-1387 SN - 1478-1395 VL - 16 IS - 4 SP - 835 EP - 855 PB - Oxford Univ. Press CY - Oxford ER - TY - RPRT A1 - Zimmermann, Andreas A1 - Boos, Felix T1 - Bringing States to Justice for Crimes against Humanity BT - The Compromissory Clause in the ILC Draft Convention on Crimes against Humanity T2 - KFG Working Paper Series N2 - Draft Art. 15 CCAH attempts to strike a balance between State autonomy and robust judicial supervision. It largely follows Article 22 CERD conditioning the jurisdiction of the ICJ on prior negotiations. Hence, the substance of the clause is interpreted in light of the Court’s recent case law, especially Georgia v. Russia. Besides, several issues regarding the scope ratione temporis of the compromissory clause are discussed. The article advances several proposals to further improve the current draft, addressing the missing explicit reference to State responsibility, as well as the relationship between the Court and a possible treaty body, It also proposes to recalibrate the interplay of a requirement of prior negotiations respectively the seizing of a future treaty body on the one hand and provisional measures to be indicated by the Court on the other. T3 - KFG Working Paper Series - 12 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-422035 SN - 2509-3770 SN - 2509-3762 IS - 12 ER - TY - JOUR A1 - Zimmermann, Andreas T1 - A victory for international rule of law? BT - Or: All's Well that ends Well? The 2017 ASP decision to amend the kampala amendment on the crime of aggression JF - Journal of international criminal justice N2 - On 14 December 2017, the Assembly of States Parties of the Rome Statute decided to activate the International Criminal Court’s jurisdiction over the crime of aggression. In doing so, it however seems to have rescinded the Kampala amendment adopted in 2010, and in particular, the need for State Parties to eventually opt out from the Court’s aggression-related jurisdiction. This reversal, while being more in line with the Rome Statute than the Kampala amendment itself, raises new (and old) and challenging legal questions which are highlighted in this article. Y1 - 2018 U6 - https://doi.org/10.1093/jicj/mqy008 SN - 1478-1387 SN - 1478-1395 VL - 16 IS - 1 SP - 19 EP - 29 PB - Oxford Univ. Press CY - Oxford ER - TY - BOOK A1 - Zhuchok, Anatolii V. T1 - Relatively free doppelsemigroups N2 - A doppelalgebra is an algebra defined on a vector space with two binary linear associative operations. Doppelalgebras play a prominent role in algebraic K-theory. We consider doppelsemigroups, that is, sets with two binary associative operations satisfying the axioms of a doppelalgebra. Doppelsemigroups are a generalization of semigroups and they have relationships with such algebraic structures as interassociative semigroups, restrictive bisemigroups, dimonoids, and trioids. In the lecture notes numerous examples of doppelsemigroups and of strong doppelsemigroups are given. The independence of axioms of a strong doppelsemigroup is established. A free product in the variety of doppelsemigroups is presented. We also construct a free (strong) doppelsemigroup, a free commutative (strong) doppelsemigroup, a free n-nilpotent (strong) doppelsemigroup, a free n-dinilpotent (strong) doppelsemigroup, and a free left n-dinilpotent doppelsemigroup. Moreover, the least commutative congruence, the least n-nilpotent congruence, the least n-dinilpotent congruence on a free (strong) doppelsemigroup and the least left n-dinilpotent congruence on a free doppelsemigroup are characterized. The book addresses graduate students, post-graduate students, researchers in algebra and interested readers. N2 - Eine Doppelalgebra ist eine auf einem Vektorraum definierte Algebra mit zwei binären linearen assoziativen Operationen. Doppelalgebren spielen eine herausragende Rolle in der algebraischen K-Theorie. Wir betrachten Doppelhalbgruppen, d.h Mengen mit zwei binären assoziativen Operationen, welche die Axiome der Doppelhalbgruppe erfüllen. Doppelhalbgruppen sind Veralgemeinerungen von Halbgruppen und sie stehen in Beziehung zu solchen algebraischen Strukturen wie interassoziative Halbgruppen, restriktive Bihalbgruppen, Dimonoiden und Trioden. In dieser Lecture Notes werden eine Vielzahl von Beispielen für Doppelhalbgruppen und strong Doppelhalbgruppen gegeben. Die Unabhängigkeit der Axiome für Doppelhalbgruppen wird nachgewiesen. Ein freies Produkt in der Varietät der Doppelhalbgruppen wird vorgestellt. Wir konstruieren auch eine freie (kommutative) strong Doppelhalbgruppe, eine freie n-dinilpotent (strong) Doppelhalbgruppe und eine freie Links n-dinilpotent Doppelhalbgruppe. Darüber hinaus werden die kleinste n-nilpotente Kogruenz, die kleinste n-dinilpotente Kongruenz auf der freien (strong) Doppelhalbgruppe und die kleinste n-dinilpotente Kongruenz auf einer freien Doppelhalbgruppe charakterisiert. Das Buch richtet sich an Graduierte, Doktoranden, Forscher in Algebra und interessierte Leser. T3 - Lectures in pure and applied mathematics - 5 KW - doppelsemigroup KW - interassociativity KW - free algebra KW - semigroup KW - congruence Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-407719 SN - 978-3-86956-427-2 SN - 2199-4951 SN - 2199-496X IS - 5 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Zhuang, Guangsheng A1 - Johnstone, Samuel A. A1 - Hourigan, Jeremy A1 - Ritts, Bradley A1 - Robinson, Alexander A1 - Sobel, Edward T1 - Understanding the geologic evolution of Northern Tibetan Plateau with multiple thermochronometers JF - Gondwana research : international geoscience journal ; official journal of the International Association for Gondwana Research N2 - The early onset of deformation following the India-Asia collision, Neogene expanse of uplift, and complex systems that comprise strike-slip faults, thrust faults, and intermontane basins characterize the Cenozoic tectonism of Northern Tibetan Plateau and raise two prominent questions in orogenic geodynamics: 1) What mechanism(s) control(s) the transfer of stress related to the India-Asia collision across the distance of >2000 km; and 2) Why the development of high topography was delayed in the Northern Tibetan Plateau and what does it reveal about how the internal forces and external boundary conditions evolved. To address these two questions, we reconstruct a holistic spatial-temporal deformation history of the Northern Tibetan Plateau by using a range of thermochronometers, with closure temperature spanning from 350 degrees C to-60-70 degrees C. This multi-thermochronometer study reveals three stages of faulting related cooling, in the early Cretaceous, in Paleocene-Eocene and in middle-late Miocene. We observe that Paleocene-Eocene deformation was spatially restricted and mostly occurred on reactivated Cretaceous structures, indicating a control of pre-existing weakness on early Cenozoic deformation. Extensive Neogene deformation contrasts with restricted Paleocene-Eocene deformation and relatively quiescent shortening during the Oligocene-early Miocene, which implies a change in the regional tectonics regime. Global plate reconstructions show that this tectonic reorganization is coeval with an increase in Pacific-Asia plate convergence rates. We argue that this change in regional tectonics is a result of increasing constrictive environment of the eastern plate boundary, which changed the behavior of the Altyn Tagh fault the boundary fault of Northern Tibetan Plateau, causing it to change from feeding slip into structures out of the plateau to feeding slip into structures at plateau margins. KW - Northern Tibetan Plateau KW - Thermochronology KW - Altyn Tagh Fault KW - Pacific-Asia convergence KW - Gravitational potential energy Y1 - 2018 U6 - https://doi.org/10.1016/j.gr.2018.02.014 SN - 1342-937X SN - 1878-0571 VL - 58 SP - 195 EP - 210 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Zhu, Hui A1 - Shprits, Yuri Y. A1 - Chen, Lunjin A1 - Liu, Xu A1 - Kellerman, Adam C. T1 - An event on simultaneous amplification of exohiss and chorus waves associated with electron density enhancements JF - Journal of geophysical research : Space physics N2 - Whistler mode exohiss are the structureless hiss waves observed outside the plasma pause with featured equatorward Poynting flux. An event of the amplification of exohiss as well as chorus waves was recorded by Van Allen Probes during the recovery phase of a weak geomagnetic storm. Amplitudes of both types of the waves showed a significant increase at the regions of electron density enhancements. It is found that the electrons resonant with exohiss and chorus showed moderate pitch angle anisotropies. The ratio of the number of electrons resonating with exohiss to total electron number presented in-phase correlation with density variations, which suggests that exohiss can be amplified due to electron density enhancement in terms of cyclotron instability. The calculation of linear growth rates further supports above conclusion. We suggest that exohiss waves have potential to become more significant due to the background plasma fluctuation. Y1 - 2018 U6 - https://doi.org/10.1029/2017JA025023 SN - 2169-9380 SN - 2169-9402 VL - 123 IS - 11 SP - 8958 EP - 8968 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Zhou, Yuefang A1 - Fischer, Martin H. T1 - Mimicking non-verbal emotional expressions and empathy development in simulated consultations BT - an experimental feasibility study JF - Patient education and counseling N2 - Objective: To explore the feasibility of applying an experimental design to study the relationship between non-verbal emotions and empathy development in simulated consultations. Method: In video-recorded simulated consultations, twenty clinicians were randomly allocated to either an experimental group (instructed to mimic non-verbal emotions of a simulated patient, SP) or a control group (no such instruction). Baseline empathy scores were obtained before consultation, relational empathy was rated by SP after consultation. Multilevel logistic regression modelled the probability of mimicry occurrence, controlling for baseline empathy and clinical experience. ANCOVA compared group differences on relational empathy and consultation smoothness. Results: Instructed mimicry lasted longer than spontaneous mimicry. Mimicry was marginally related to improved relational empathy. SP felt being treated more like a whole person during consultations with spontaneous mimicry. Clinicians who displayed spontaneous mimicry felt consultations went more smoothly. Conclusion: The experimental approach improved our understanding of how non-verbal emotional mimicry contributed to relational empathy development during consultations. Further work should ascertain the potential of instructed mimicry to enhance empathy development. Practice implications: Understanding how non-verbal emotional mimicry impacts on patients’ perceived clinician empathy during consultations may inform training and intervention programme development. KW - Mimicry KW - Non-verbal emotion KW - Empathy KW - Experimental design Y1 - 2017 U6 - https://doi.org/10.1016/j.pec.2017.08.016 SN - 0738-3991 VL - 101 IS - 2 SP - 304 EP - 309 PB - Elsevier Science CY - Clare ER - TY - JOUR A1 - Zhou, Wei A1 - Wang, Aiping A1 - Shu, Hua A1 - Kliegl, Reinhold A1 - Yan, Ming T1 - Word segmentation by alternating colors facilitates eye guidance in Chinese reading JF - Memory & cognition N2 - During sentence reading, low spatial frequency information afforded by spaces between words is the primary factor for eye guidance in spaced writing systems, whereas saccade generation for unspaced writing systems is less clear and under debate. In the present study, we investigated whether word-boundary information, provided by alternating colors (consistent or inconsistent with word-boundary information) influences saccade-target selection in Chinese. In Experiment 1, as compared to a baseline (i.e., uniform color) condition, word segmentation with alternating color shifted fixation location towards the center of words. In contrast, incorrect word segmentation shifted fixation location towards the beginning of words. In Experiment 2, we used a gaze-contingent paradigm to restrict the color manipulation only to the upcoming parafoveal words and replicated the results, including fixation location effects, as observed in Experiment 1. These results indicate that Chinese readers are capable of making use of parafoveal word-boundary knowledge for saccade generation, even if such information is unfamiliar to them. The present study provides novel support for the hypothesis that word segmentation is involved in the decision about where to fixate next during Chinese reading. KW - Chinese KW - Word segmentation KW - Fixation location KW - Parafoveal KW - Color Y1 - 2018 U6 - https://doi.org/10.3758/s13421-018-0797-5 SN - 0090-502X SN - 1532-5946 VL - 46 IS - 5 SP - 729 EP - 740 PB - Springer CY - New York ER - TY - JOUR A1 - Zhong, Qi A1 - Mi, Lei A1 - Metwalli, Ezzeldin A1 - Biessmann, Lorenz A1 - Philipp, Martine A1 - Miasnikova, Anna A1 - Laschewsky, Andre A1 - Papadakis, Christine M. A1 - Cubitt, Robert A1 - Schwartzkopf, Matthias A1 - Roth, Stephan V. A1 - Wang, Jiping A1 - Müller-Buschbaum, Peter T1 - Effect of chain architecture on the swelling and thermal response of star-shaped thermo-responsive (poly(methoxy diethylene glycol acrylate)-block-polystyrene)(3) block copolymer films JF - Soft matter N2 - The effect of chain architecture on the swelling and thermal response of thin films obtained from an amphiphilic three-arm star-shaped thermo-responsive block copolymer poly(methoxy diethylene glycol acrylate)-block-polystyrene ((PMDEGA-b-PS)(3)) is investigated by in situ neutron reflectivity (NR) measurements. The PMDEGA and PS blocks are micro-phase separated with randomly distributed PS nanodomains. The (PMDEGA-b-PS)(3) films show a transition temperature (TT) at 33 degrees C in white light interferometry. The swelling capability of the (PMDEGA-b-PS)(3) films in a D2O vapor atmosphere is better than that of films from linear PS-b-PMDEGA-b-PS triblock copolymers, which can be attributed to the hydrophilic end groups and limited size of the PS blocks in (PMDEGA-b-PS)(3). However, the swelling kinetics of the as-prepared (PMDEGA-b-PS)(3) films and the response of the swollen film to a temperature change above the TT are significantly slower than that in the PS-b-PMDEGA-b-PS films, which may be related to the conformation restriction by the star-shape. Unlike in the PS-b-PMDEGA-b-PS films, the amount of residual D2O in the collapsed (PMDEGA-b-PS)(3) films depends on the final temperature. It decreases from (9.7 +/- 0.3)% to (7.0 +/- 0.3)% or (6.0 +/- 0.3)% when the final temperatures are set to 35 degrees C, 45 degrees C and 50 degrees C, respectively. This temperature-dependent reduction of embedded D2O originates from the hindrance of chain conformation from the star-shaped chain architecture. Y1 - 2018 U6 - https://doi.org/10.1039/c8sm00965a SN - 1744-683X SN - 1744-6848 VL - 14 IS - 31 SP - 6582 EP - 6594 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Zhivkova, Veselina A1 - Kiecker, Felix A1 - Langer, Peter A1 - Eberle, Jürgen T1 - Crucial role of reactive oxygen species (ROS) for the proapoptotic effects of indirubin derivative DKP-073 in melanoma cells JF - Molecular carcinogenesis N2 - Melanoma represents a prime example demonstrating the success of targeted therapy in cancer. Nevertheless, it remained a deadly disease until now, and the identification of new, independent strategies as well as the understanding of their molecular mechanisms may help to finally overcome the high mortality. Both indirubins and TNF-related apoptosis-inducing ligand (TRAIL) represent promising candidates. Here, the indirubin derivative DKP-073 is shown to trigger apoptosis in melanoma cells, which is enhanced by the combination with TRAIL and is accompanied by complete loss of cell viability. Addressing the signaling cascade, characteristic molecular steps were identified as caspase-3 activation, downregulation of XIAP, upregulation of p53 and TRAIL receptor 2, loss of mitochondrial membrane potential, and STAT-3 dephosphorylation. The decisive step, however, turned out to be the early production of ROS already at 1 h. This was proven by antioxidant pretreatment, which completely abolished apoptosis induction and loss of cell viability as well as abrogated all signaling effects listed above. Thus, ROS appeared as upstream of all proapoptotic signaling. The data indicate a dominant role of ROS in apoptosis regulation, and the new pathway may expose a possible Achilles heel of melanoma. KW - apoptosis KW - kinase pathway KW - melanoma KW - stat 3 Y1 - 2018 U6 - https://doi.org/10.1002/mc.22924 SN - 0899-1987 SN - 1098-2744 VL - 58 IS - 2 SP - 258 EP - 269 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Zheng, Chunming A1 - Pikovskij, Arkadij T1 - Delay-induced stochastic bursting in excitable noisy systems JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - We show that a combined action of noise and delayed feedback on an excitable theta-neuron leads to rather coherent stochastic bursting. An idealized point process, valid if the characteristic timescales in the problem are well separated, is used to describe statistical properties such as the power spectral density and the interspike interval distribution. We show how the main parameters of the point process, the spontaneous excitation rate, and the probability to induce a spike during the delay action can be calculated from the solutions of a stationary and a forced Fokker-Planck equation. Y1 - 2018 U6 - https://doi.org/10.1103/PhysRevE.98.042148 SN - 2470-0045 SN - 2470-0053 VL - 98 IS - 4 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Zheng, Botuo A1 - Bai, Tianwen A1 - Tao, Xinfeng A1 - Schlaad, Helmut A1 - Ling, Jun T1 - Identifying the Hydrolysis of Carbonyl Sulfide as a Side Reaction Impeding the Polymerization of N-Substituted Glycine N-Thiocarboxyanhydride JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - Polypeptoids are noticeable biological materials due to their versatile properties and various applications in drug delivery, surface modification, self-assembly, etc. N-Substituted glycine N-thiocarboxyanhydrides (NNTAs) are more stable monomers than the corresponding N-carboxyanhydrides (NNCAs) and enable one to prepare polypeptoids via ring-opening polymerization even in the presence of water. However, larger amounts of water (>10,000 ppm) cause inhibition of the polymerization. Herein, we discover that during polymerization hydrogen sulfide evolves from the hydrolysis of carbonyl sulfide, which is the byproduct of ring-opening reaction, and reacts with NNTA to produce cyclic oligopeptoids. The capture of N-ethylethanethioic acid as an intermediate product confirms the reaction mechanism together with density functional theory quantum computational results. By bubbling the polymerization solution with argon, the side reaction can be suppressed to allow the synthesis of polysarcosine with high molar mass (M-n = 11,200 g/mol, D = 1.25) even in the presence of similar to 10,000 ppm of water. Y1 - 2018 U6 - https://doi.org/10.1021/acs.biomac.8b01119 SN - 1525-7797 SN - 1526-4602 VL - 19 IS - 11 SP - 4263 EP - 4269 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Zhao, Liming A1 - Xia, Yan A1 - Wu, Xiao-Yuan A1 - Schippers, Jos H. M. A1 - Jing, Hai-Chun T1 - Phenotypic analysis and molecular markers of leaf senescence JF - Plant Senescence: Methods and Protocols N2 - The process of leaf senescence consists of the final stage of leaf development. It has evolved as a mechanism to degrade macromolecules and micronutrients and remobilize them to other developing parts of the plant; hence it plays a central role for the survival of plants and crop production. During senescence, a range of physiological, morphological, cellular, and molecular events occur, which are generally referred to as the senescence syndrome that includes several hallmarks such as visible yellowing, loss of chlorophyll and water content, increase of ion leakage and cell death, deformation of chloroplast and cell structure, as well as the upregulation of thousands of so-called senescence-associated genes (SAGs) and downregulation of photosynthesis-associated genes (PAGs). This chapter is devoted to methods characterizing the onset and progression of leaf senescence at the morphological, physiological, cellular, and molecular levels. Leaf senescence normally progresses in an age-dependent manner but is also induced prematurely by a variety of environmental stresses in plants. Focused on the hallmarks of the senescence syndrome, a series of protocols is described to asses quantitatively the senescence process caused by developmental cues or environmental perturbations. We first briefly describe the senescence process, the events associated with the senescence syndrome, and the theories and methods to phenotype senescence. Detailed protocols for monitoring senescence in planta and in vitro, using the whole plant and the detached leaf, respectively, are presented. For convenience, most of the protocols use the model plant species Arabidopsis and rice, but they can be easily extended to other plants. KW - Leaf senescence KW - Visible yellowing KW - Chlorophyll KW - Ion leakage KW - Cell death KW - Senescence-associated genes (SAGs) KW - Arabidopsis KW - Rice Y1 - 2018 SN - 978-1-4939-7672-0 SN - 978-1-4939-7670-6 U6 - https://doi.org/10.1007/978-1-4939-7672-0_3 SN - 1064-3745 SN - 1940-6029 VL - 1744 SP - 35 EP - 48 PB - Humana Press Inc. CY - Totowa ER - TY - JOUR A1 - Zhang, Yang A1 - Huang, Wentao A1 - Huang, Baochun A1 - van Hinsbergen, Douwe J. J. A1 - Yang, Tao A1 - Dupont-Nivet, Guillaume A1 - Guo, Zhaojie T1 - 53-43Ma Deformation of Eastern Tibet Revealed by Three Stages of Tectonic Rotation in the Gongjue Basin JF - Journal of geophysical research : Solid earth N2 - The Gongjue basin from the eastern Qiangtang terrane is located in the transition region where the regional structural lineation curves from east-west-oriented in Tibet to north-south-oriented in Yunnan. In this study, we sampled the red beds in the basin from the lower Gongjue to upper Ranmugou formations for the first time covering the entire stratigraphic profile. The stratigraphic ages are bracketed within 53-43Ma by new detrital zircon U-Pb ages constraining the maximum deposition age to 52.51.5Ma. Rock magnetic and petrographic studies indicate that detrital magnetite and hematite are the magnetic carriers. Positive reversals and fold tests demonstrate that the characteristic remanent magnetization has a primary origin. The Gongjue and Ranmugou formations yield mean characteristic remanent magnetization directions of D-s/I-s=31.0 degrees/21.3 degrees and D-s/I-s=15.9 degrees/22.0 degrees, respectively. The magnetic inclination of these characteristic remanent magnetizations is significantly shallowed compared to the expected inclination for the locality. However, the elongation/inclination correction method does not provide a meaningful correction, likely because of syn-depositional rotation. Rotations relative to the Eurasian apparent polar wander path occurred in three stages: Stage I, 33.33.4 degrees clockwise rotation during the deposition of the Gongjue and lower Ranmugou formations; Stage II, 26.93.7 degrees counterclockwise rotation during deposition of the lower and middle Ranmugou formation; and Stage III, 17.73.3 degrees clockwise rotation after 43Ma. The complex rotation history recorded in the basin is possibly linked to sinistral shear along the Qiangtang block during India indentation into Asia and the early stage of the extrusion of the northwestern Indochina blocks away from eastern Tibet. KW - eastern Qiangtang terrane KW - Gongjue basin KW - paleomagnetism KW - inclination shallowing KW - rotation Y1 - 2018 U6 - https://doi.org/10.1002/2018JB015443 SN - 2169-9313 SN - 2169-9356 VL - 123 IS - 5 SP - 3320 EP - 3338 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Zhang, Xiaorong A1 - Yarman, Aysu A1 - Erdossy, Julia A1 - Katz, Sagie A1 - Zebger, Ingo A1 - Jetzschmann, Katharina J. A1 - Altintas, Zeynep A1 - Wollenberger, Ulla A1 - Gyurcsanyi, Robert E. A1 - Scheller, Frieder W. T1 - Electrosynthesized MIPs for transferrin BT - Plastibodies or nano-filters? JF - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics N2 - Molecularly imprinted polymer (MP) nanofilrns for transferrin (Trf) have been synthesized on gold surfaces by electro-polymerizing the functional monomer scopoletin in the presence of the protein target or around pre-adsorbed Trf. As determined by atomic force microscopy (AFM) the film thickness was comparable with the molecular dimension of the target. The target (re)binding properties of the electro-synthesized MIP films was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV) through the target-binding induced permeability changes of the MIP nanofilms to the ferricyanide redox marker, as well as by surface plasmon resonance (SPR) and surface enhanced infrared absorption spectroscopy (SEIRAS) of the immobilized protein molecules. For Trf a linear concentration dependence in the lower micromolar range and an imprinting factor of similar to 5 was obtained by SWV and SPR. Furthermore, non-target proteins including the iron-free apo-Trf were discriminated by pronounced size and shape specificity. Whilst it is generally assumed that the rebinding of the target or of cross-reacting proteins exclusively takes place at the polymer here we considered also the interaction of the protein molecules with the underlying gold transducers. We demonstrate by SWV that adsorption of proteins suppresses the signal of the redox marker even at the bare gold surface and by SEIRAS that the treatment of the MIP with proteinase K or NaOH only partially removes the target protein. Therefore, we conclude that when interpreting binding of proteins to directly MIP-covered gold electrodes the interactions between the protein and the gold surface should also be considered. KW - Molecularly imprinted polymer KW - Scopoletin KW - Transferrin KW - Protein adsorption KW - Redox marker Y1 - 2018 U6 - https://doi.org/10.1016/j.bios.2018.01.011 SN - 0956-5663 SN - 1873-4235 VL - 105 SP - 29 EP - 35 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zhang, Shanshan A1 - Stolterfoht, Martin A1 - Armin, Ardalan A1 - Lin, Qianqian A1 - Zu, Fengshuo A1 - Sobus, Jan A1 - Jin, Hui A1 - Koch, Norbert A1 - Meredith, Paul A1 - Burn, Paul L. A1 - Neher, Dieter T1 - Interface Engineering of Solution-Processed Hybrid Organohalide Perovskite Solar Cells JF - ACS applied materials & interfaces N2 - Engineering the interface between the perovskite absorber and the charge-transporting layers has become an important method for improving the charge extraction and open-circuit voltage (V-OC) of hybrid perovskite solar cells. Conjugated polymers are particularly suited to form the hole-transporting layer, but their hydrophobicity renders it difficult to solution-process the perovskite absorber on top. Herein, oxygen plasma treatment is introduced as a simple means to change the surface energy and work function of hydrophobic polymer interlayers for use as p-contacts in perovskite solar cells. We find that upon oxygen plasma treatment, the hydrophobic surfaces of different prototypical p-type polymers became sufficiently hydrophilic to enable subsequent perovskite junction processing. In addition, the oxygen plasma treatment also increased the ionization potential of the polymer such that it became closer to the valance band energy of the perovskite. It was also found that the oxygen plasma treatment could increase the electrical conductivity of the p-type polymers, facilitating more efficient charge extraction. On the basis of this concept, inverted MAPbI(3) perovskite devices with different oxygen plasma-treated polymers such as P3HT, P3OT, polyTPD, or PTAA were fabricated with power conversion efficiencies of up to 19%. KW - organohalide lead perovskites KW - solar cells KW - surface wetting KW - work function KW - oxygen plasma KW - transport layer Y1 - 2018 U6 - https://doi.org/10.1021/acsami.8b02503 SN - 1944-8244 VL - 10 IS - 25 SP - 21681 EP - 21687 PB - American Chemical Society CY - Washington ER - TY - THES A1 - Zhang, Quanchao T1 - Shape-memory properties of polymeric micro-scale objects prepared by electrospinning and electrospraying N2 - The ongoing trend of miniaturizing multifunctional devices, especially for minimally-invasive medical or sensor applications demands new strategies for designing the required functional polymeric micro-components or micro-devices. Here, polymers, which are capable of active movement, when an external stimulus is applied (e.g. shape-memory polymers), are intensively discussed as promising material candidates for realization of multifunctional micro-components. In this context further research activities are needed to gain a better knowledge about the underlying working principles for functionalization of polymeric micro-scale objects with a shape-memory effect. First reports about electrospun solid microfiber scaffolds, demonstrated a much more pronounced shape-memory effect than their bulk counterparts, indicating the high potential of electrospun micro-objects. Based on these initial findings this thesis was aimed at exploring whether the alteration of the geometry of micro-scale electrospun polymeric objects can serve as suitable parameter to tailor their shape-memory properties. The central hypothesis was that different geometries should result in different degrees of macromolecular chain orientation in the polymeric micro-scale objects, which will influence their mechanical properties as well as thermally-induced shape-memory function. As electrospun micro-scale objects, microfiber scaffolds composed of hollow microfibers with different wall thickness and electrosprayed microparticles as well as their magneto-sensitive nanocomposites all prepared from the same polymer exhibiting pronounced bulk shape-memory properties were investigated. For this work a thermoplastic multiblock copolymer, named PDC, with excellent bulk shape-memory properties, associated with crystallizable oligo(ε-caprolactone) (OCL) switching domains, was chosen for the preparation of electrospun micro-scale objects, while crystallizable oligo(p-dioxanone) (OPDO) segments serve as hard domains in PDC. In the first part of the thesis microfiber scaffolds with different microfiber geometries (solid or hollow with different wall thickness) were discussed. Hollow microfiber based PDC scaffolds were prepared by coaxial electrospinning from a 1, 1, 1, 3, 3, 3 hexafluoro-2-propanol (HFP) solution with a polymer concentration of 13% w·v-1. Here as a first step core-shell fiber scaffolds consisting of microfibers with a PDC shell and sacrificial poly(ethylene glycol) (PEG) core are generated. The hollow PDC microfibers were achieved after dissolving the PEG core with water. The utilization of a fixed electrospinning setup and the same polymer concentration of the PDC spinning solution could ensure the fabrication of microfibers with almost identical outer diameters of 1.4 ± 0.3 µm as determined by scanning electron microscopy (SEM). Different hollow microfiber wall thicknesses of 0.5 ± 0.2 and 0.3 ± 0.2 µm (analyzed by SEM) have been realized by variation of the mass flow rate, while solid microfibers were obtained by coaxial electrospinning without supplying any core solution. Differential scanning calorimetry experiments and tensile tests at ambient temperature revealed an increase in degree of OCL crystallinity form χc,OCL = 34 ± 1% to 43 ± 1% and a decrease in elongation of break from 800 ± 40% to 200 ± 50% associated with an increase in Young´s modulus and failture stress for PDC hollow microfiber scaffolds when compared with soild fibers. The observed effects were enhanced with decreasing wall thickness of the single hollow fibers. The shape-memory properties of the electrospun PDC scaffolds were quantified by cyclic, thermomechanical tensile tests. Here, scaffolds comprising hollow microfibers exhibited lower shape fixity ratios around Rf = 82 ± 1% and higher shape recovery ratios of Rr = 67 ± 1% associated to more pronounced relaxation at constant strain during the first test cycle and a lower switching temperature of Tsw = 33 ± 1 °C than the fibrous meshes consisting of solid microfibers. These findings strongly support the central hypothesis that different fiber geometries (solid or hollow with different wall thickness) in electrospun scaffolds result in different degrees of macromolecular chain orientation in the polymeric micro-scale objects, which can be applied as design parameter for tailoring their mechanical and shape-memory properties. The second part of the thesis deals with electrosprayed particulate PDC micro-scale objects. Almost spherical PDC microparticles with diameters of 3.9 ± 0.9 μm (as determined by SEM) were achieved by electrospraying of HFP solution with a polymer concentration of 2% w·v-1. In contrast, smaller particles with sizes of 400 ± 100 nm or 1.2 ± 0.3 μm were obtained for the magneto-sensitive composite PDC microparticles containing 23 ± 0.5 wt% superparamagnetic magnetite nanoparticles (mNPs). All prepared PDC microparticles exhibited a similar overall crystallinity like the PDC bulk material as analyzed by DSC. AFM nanoindentation results revealed no influence of the nanofiller incorporation on the local mechanical properties represented by the reduced modulus determined for pure PDC microparticles and magneto-sensitive composite PDC microparticles with similar diameters around 1.3 µm. It was found that the reduced modulus of the nanocomposite microparticles increased substantially with decreasing particles size from 2.4 ± 0.9 GPa (1.2 µm) to 11.9 ± 3.1 GPa (0.4 µm), which can be related to a higher orientation of the macromolecules at the surface of smaller sized microparticles. The magneto-sensitivity of such nanocomposite microparticles could be demonstrated in two aspects. One was by attracting/collecting the composite micro-objects with an external permanent magnet. The other one was by a inductive heating to 44 ± 1 °C, which is well above the melting transition of the OCL switching domains, when compacted to a 10 x 10 mm2 film with a thickness of 10 µm and exposed to an alternating magnet field with an magnetic field strength of 30 kA·m-1. Both functions are of great relevance for designing next generation drug delivery systems combining targeting and on demand release. By a compression approach shape-memory functionalization of individual microparticles could be realized. Here different programming pressures and compression temperatures were applied. The shape-recovery capability of the programmed PDC microparticles was quantified by online and off-line heating experiments analyzed via microscopy measurement. The obtained shape-memory properties were found to be strongly depending on the applied programming pressure and temperature. The best shape-memory performance with a high shape recovery rate of about Rr = 80±1% was obtained when a low pressure of 0.2 MPa was applied at 55 °C. Finally, it was demonstrated that PDC microparticles can be utilized as micro building parts for preparation of a macroscopic film with temporary stability by compression of a densely packed array of PDC microparticles at 60 °C followed by subsequent cooling to ambient temperature. This film disintegrates into individual microparticles upon heating to 60 °C. Based on this technology the design of stable macroscopic release systems can be envisioned, which can be easily fixed at the site of treatment (i.e. by suturing) and disintegrate on demand to microparticles facilitating the drug release. In summary, the results of this thesis could confirm the central hypothesis that the variation of the geometry of polymeric micro-objects is a suitable parameter to adjust their shape-memory performance by changing the degree of macromolecular chain orientation in the specimens or by enabling new functions like on demand disintegration. These fundamental findings might be relevant for designing novel miniaturized multifunctional polymer-based devices. KW - shape-memory effect KW - microparticles KW - hollow microfibers KW - geometry Y1 - 2018 ER - TY - JOUR A1 - Zhang, Heshou A1 - Yan, Huirong A1 - Richter, Philipp T1 - The influence of atomic alignment on absorption and emission spectroscopy JF - Monthly notices of the Royal Astronomical Society N2 - Spectroscopic observations play essential roles in astrophysics. They are crucial for determining physical parameters in our Universe, providing information about the chemistry of various astronomical environments. The proper execution of the spectroscopic analysis requires accounting for all the physical effects that are compatible to the signal-to-noise ratio. We find in this paper the influence on spectroscopy from the atomic/ground state alignment owing to anisotropic radiation and modulated by interstellar magnetic field, has significant impact on the study of interstellar gas. In different observational scenarios, we comprehensively demonstrate how atomic alignment influences the spectral analysis and provide the expressions for correcting the effect. The variations are even more pronounced for multiplets and line ratios. We show the variation of the deduced physical parameters caused by the atomic alignment effect, including alpha-to-iron ratio ([X/Fe]) and ionization fraction. Synthetic observations are performed to illustrate the visibility of such effect with current facilities. A study of Photodissociation regions in rho Ophiuchi cloud is presented to demonstrate how to account for atomic alignment in practice. Our work has shown that due to its potential impact, atomic alignment has to be included in an accurate spectroscopic analysis of the interstellar gas with current observational capability. KW - magnetic fields KW - submillimetre: ISM KW - ultraviolet: ISM KW - ISM: abundances KW - ISM: lines and bands KW - techniques: spectroscopic Y1 - 2018 U6 - https://doi.org/10.1093/mnras/sty1594 SN - 0035-8711 SN - 1365-2966 VL - 479 IS - 3 SP - 3923 EP - 3935 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Zhang, Heshou A1 - Yan, Huirong T1 - Polarization of submillimetre lines from interstellar medium JF - Monthly notices of the Royal Astronomical Society N2 - Magnetic fields play important roles in many astrophysical processes. However, there is no universal diagnostic for the magnetic fields in the interstellar medium (ISM) and each magnetic tracer has its limitation. Any new detection method is thus valuable. Theoretical studies have shown that submillimetre fine-structure lines are polarized due to atomic alignment by ultraviolet photon-excitation, which opens up a new avenue to probe interstellar magnetic fields. We will, for the first time, perform synthetic observations on the simulated three-dimensional ISM to demonstrate the measurability of the polarization of submillimetre atomic lines. The maximum polarization for different absorption and emission lines expected from various sources, including star-forming regions are provided. Our results demonstrate that the polarization of submillimetre atomic lines is a powerful magnetic tracer and add great value to the observational studies of the submilimetre astronomy. KW - polarization KW - turbulence KW - H II regions KW - ISM: magnetic fields KW - photodissociation region (PDR) KW - submillimetre: ISM Y1 - 2017 U6 - https://doi.org/10.1093/mnras/stx3164 SN - 0035-8711 SN - 1365-2966 VL - 475 IS - 2 SP - 2415 EP - 2420 PB - Oxford University Press CY - Oxford ER - TY - GEN A1 - Zemella, Anne A1 - Thoring, Lena A1 - Hoffmeister, Christian A1 - Šamalíková, Mária A1 - Ehren, Patricia A1 - Wüstenhagen, Doreen Anja A1 - Kubick, Stefan T1 - Cell-free protein synthesis as a novel tool for directed glycoengineering of active erythropoietin T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - As one of the most complex post-translational modification, glycosylation is widely involved in cell adhesion, cell proliferation and immune response. Nevertheless glycoproteins with an identical polypeptide backbone mostly differ in their glycosylation patterns. Due to this heterogeneity, the mapping of different glycosylation patterns to their associated function is nearly impossible. In the last years, glycoengineering tools including cell line engineering, chemoenzymatic remodeling and site-specific glycosylation have attracted increasing interest. The therapeutic hormone erythropoietin (EPO) has been investigated in particular by various groups to establish a production process resulting in a defined glycosylation pattern. However commercially available recombinant human EPO shows batch-to-batch variations in its glycoforms. Therefore we present an alternative method for the synthesis of active glycosylated EPO with an engineered O-glycosylation site by combining eukaryotic cell-free protein synthesis and site-directed incorporation of non-canonical amino acids with subsequent chemoselective modifications. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 824 KW - recombinat-human-erythropoietin KW - glycosylation KW - expression KW - site KW - anemia KW - CDNA KW - glycoprotein KW - purification KW - cloning KW - growth Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427017 IS - 824 ER - TY - JOUR A1 - Zemella, Anne A1 - Thoring, Lena A1 - Hoffmeister, Christian A1 - Samalikova, Maria A1 - Ehren, Patricia A1 - Wüstenhagen, Doreen Anja A1 - Kubick, Stefan T1 - Cell-free protein synthesis as a novel tool for directed glycoengineering of active erythropoietin JF - Scientific reports N2 - As one of the most complex post-translational modification, glycosylation is widely involved in cell adhesion, cell proliferation and immune response. Nevertheless glycoproteins with an identical polypeptide backbone mostly differ in their glycosylation patterns. Due to this heterogeneity, the mapping of different glycosylation patterns to their associated function is nearly impossible. In the last years, glycoengineering tools including cell line engineering, chemoenzymatic remodeling and site-specific glycosylation have attracted increasing interest. The therapeutic hormone erythropoietin (EPO) has been investigated in particular by various groups to establish a production process resulting in a defined glycosylation pattern. However commercially available recombinant human EPO shows batch-to-batch variations in its glycoforms. Therefore we present an alternative method for the synthesis of active glycosylated EPO with an engineered O-glycosylation site by combining eukaryotic cell-free protein synthesis and site-directed incorporation of non-canonical amino acids with subsequent chemoselective modifications. Y1 - 2018 U6 - https://doi.org/10.1038/s41598-018-26936-x SN - 2045-2322 VL - 8 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Zellmeier, M. A1 - Brenner, Thomas J. K. A1 - Janietz, Silvia A1 - Nickel, N. H. A1 - Rappich, J. T1 - Polythiophenes as emitter layers for crystalline silicon solar cells BT - parasitic absorption, interface passivation, and open circuit voltage JF - Journal of applied physics N2 - We investigated the influence of the emitter (amorphous-Si, a-Si, or polythiophene derivatives: poly(3-hexylthiophene), P3HT, and poly(3-[3,6-dioxaheptyl]-thiophene), P3DOT) and the interface passivation (intrinsic a-Si or SiOX and methyl groups or SiOX) on the c-Si based 1 × 1 cm2 planar hybrid heterojunction solar cell parameters. We observed higher short circuit currents for the P3HT or P3DOT/c-Si solar cells than those obtained for a-Si/c-Si devices, independent of the interface passivation. The obtained VOC of 659 mV for the P3DOT/SiOX/c-Si heterojunction solar cell with hydrophilic 3,6-dioxaheptyl side chains is among the highest reported for c-Si/polythiophene devices. The maximum power conversion efficiency, PCE, was 11% for the P3DOT/SiOX/c-Si heterojunction solar cell. Additionally, our wafer lifetime measurements reveal a field effect passivation in the wafer induced by the polythiophenes when deposited on c-Si. Y1 - 2018 U6 - https://doi.org/10.1063/1.5006625 SN - 0021-8979 SN - 1089-7550 VL - 123 IS - 3 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Zapata, Sebastian Henao A1 - Cardona, A. A1 - Jaramillo, J. S. A1 - Patino, A. A1 - Valencia, V. A1 - Leon, S. A1 - Mejia, D. A1 - Pardo-Trujillo, A. A1 - Castaneda, J. P. T1 - Cretaceous extensional and compressional tectonics in the Northwestern Andes, prior to the collision with the Caribbean oceanic plateau JF - Gondwana research : international geoscience journal ; official journal of the International Association for Gondwana Research N2 - The Cretaceous units exposed in the northwestern segment of the Colombian Andes preserve the record of extensional and compressional tectonics prior to the collision with Caribbean oceanic terranes. We integrated field, stratigraphic, sedimentary provenance, whole rock geochemistry, Nd isotopes and U-Pb zircon data to understand the Cretaceous tectonostratigraphic and magmatic record of the Colombian Andes. The results suggest that several sedimentary successions including the Abejorral Fm. were deposited on top of the continental basement in an Early Cretaceous backarc basin (150-100 Ma). Between 120 and 100 Ma, the appearance of basaltic and andesitic magmatism (similar to 115-100 Ma), basin deepening, and seafloor spreading were the result of advanced stages of backarc extension. A change to compressional tectonics took place during the Late Cretaceous (100-80 Ma). During this compressional phase, the extended blocks were reincorporated into the margin, closing the former Early Cretaceous backarc basin. Subsequently, a Late Cretaceous volcanic arc was built on the continental margin: as a result, the volcanic rocks of the Quebradagrande Complex were unconformably deposited on top of the faulted and folded rocks of the Abejorral Fm. Between the Late Cretaceous and the Paleocene (80-60 Ma), an arc-continent collision between the Caribbean oceanic plateau and the South-American continental margin deformed the rocks of the Quebradagrande Complex and shut-down the active volcanic arc. Our results suggest an Early Cretaceous extensional event followed by compressional tectonics prior to the collision with the Caribbean oceanic plateau. (C) 2019 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. KW - Northern Andes KW - Paleogeography KW - Cretaceous KW - Extension KW - Convergent margins KW - Provenance Y1 - 2018 U6 - https://doi.org/10.1016/j.gr.2018.10.008 SN - 1342-937X SN - 1878-0571 VL - 66 SP - 207 EP - 226 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Zakariás, Lilla T1 - Transfer effects after working memory training in post-stroke aphasia T1 - Transfereffekte nach Arbeitsgedächtnistraining bei Aphasie nach Schlaganfall N2 - Background: Individuals with aphasia after stroke (IWA) often present with working memory (WM) deficits. Research investigating the relationship between WM and language abilities has led to the promising hypothesis that treatments of WM could lead to improvements in language, a phenomenon known as transfer. Although recent treatment protocols have been successful in improving WM, the evidence to date is scarce and the extent to which improvements in trained tasks of WM transfer to untrained memory tasks, spoken sentence comprehension, and functional communication is yet poorly understood. Aims: We aimed at (a) investigating whether WM can be improved through an adaptive n-back training in IWA (Study 1–3); (b) testing whether WM training leads to near transfer to unpracticed WM tasks (Study 1–3), and far transfer to spoken sentence comprehension (Study 1–3), functional communication (Study 2–3), and memory in daily life in IWA (Study 2–3); and (c) evaluating the methodological quality of existing WM treatments in IWA (Study 3). To address these goals, we conducted two empirical studies – a case-controls study with Hungarian speaking IWA (Study 1) and a multiple baseline study with German speaking IWA (Study 2) – and a systematic review (Study 3). Methods: In Study 1 and 2 participants with chronic, post-stroke aphasia performed an adaptive, computerized n-back training. ‘Adaptivity’ was implemented by adjusting the tasks’ difficulty level according to the participants’ performance, ensuring that they always practiced at an optimal level of difficulty. To assess the specificity of transfer effects and to better understand the underlying mechanisms of transfer on spoken sentence comprehension, we included an outcome measure testing specific syntactic structures that have been proposed to involve WM processes (e.g., non-canonical structures with varying complexity). Results: We detected a mixed pattern of training and transfer effects across individuals: five participants out of six significantly improved in the n-back training. Our most important finding is that all six participants improved significantly in spoken sentence comprehension (i.e., far transfer effects). In addition, we also found far transfer to functional communication (in two participants out of three in Study 2) and everyday memory functioning (in all three participants in Study 2), and near transfer to unpracticed n-back tasks (in four participants out of six). Pooled data analysis of Study 1 and 2 showed a significant negative relationship between initial spoken sentence comprehension and the amount of improvement in this ability, suggesting that the more severe the participants’ spoken sentence comprehension deficit was at the beginning of training, the more they improved after training. Taken together, we detected both near far and transfer effects in our studies, but the effects varied across participants. The systematic review evaluating the methodological quality of existing WM treatments in stroke IWA (Study 3) showed poor internal and external validity across the included 17 studies. Poor internal validity was mainly due to use of inappropriate design, lack of randomization of study phases, lack of blinding of participants and/or assessors, and insufficient sampling. Low external validity was mainly related to incomplete information on the setting, lack of use of appropriate analysis or justification for the suitability of the analysis procedure used, and lack of replication across participants and/or behaviors. Results in terms of WM, spoken sentence comprehension, and reading are promising, but further studies with more rigorous methodology and stronger experimental control are needed to determine the beneficial effects of WM intervention. Conclusions: Results of the empirical studies suggest that WM can be improved with a computerized and adaptive WM training, and improvements can lead to transfer effects to spoken sentence comprehension and functional communication in some individuals with chronic post-stroke aphasia. The fact that improvements were not specific to certain syntactic structures (i.e., non-canonical complex sentences) in spoken sentence comprehension suggest that WM is not involved in the online, automatic processing of syntactic information (i.e., parsing and interpretation), but plays a more general role in the later stage of spoken sentence comprehension (i.e., post-interpretive comprehension). The individual differences in treatment outcomes call for future research to clarify how far these results are generalizable to the population level of IWA. Future studies are needed to identify a few mechanisms that may generalize to at least a subpopulation of IWA as well as to investigate baseline non-linguistic cognitive and language abilities that may play a role in transfer effects and the maintenance of such effects. These may require larger yet homogenous samples. N2 - Patienten mit einer Aphasie nach einem Schlaganfall weisen häufig auch Beeinträchtigungen des Arbeitsgedächtnisses auf. Studien, die das Zusammenspiel von Arbeitsgedächtnis und Sprachfähigkeit untersuchen führten zu der Hypothese, dass ein Training des Arbeitsgedächtnisses auch zu Verbesserungen der Sprache führen könnten (sogenannte Transfer-Effekte). Obwohl jüngste Therapiestudien nachweislich die Leistung des Arbeitsgedächtnisses verbessern konnten, gibt es derzeitig nur wenig Evidenzen, ob und in welchem Ausmaß sich Verbesserungen des Arbeitsgedächtnisses auch auf ungeübte Gedächtnisaufgaben, das auditive Satzverständnis und die Kommunikationsfähigkeit im Alltag auswirken können. Das vorliegende Dissertationsprojekt untersucht, ob (a) das Arbeitsgedächtnis bei Patienten mit einer Aphasie über ein adaptiertes N-Back-Training verbessert werden kann (Studie 1–3) und (b) das Arbeitsgedächtnistraining zu einem nahen Transfer auf ungeübte Arbeitsgedächtnisaufgaben (Studie 1–3) und zu einem weiten Transfer auf auditive Satzverständnisaufgaben (Studie 1–3), auf die Alltagskommunikation (Studie 2–3) und auf das Alltagsgedächtnis (Studie 2–3) bei Patienten mit einer Aphasie führt. Zudem evaluiert das vorliegende Projekt (c) die methodische Qualität bereits existierender Arbeitsgedächtnistrainings bei Patienten mit einer Aphasie (Studie 3). Zur Beantwortung der vorliegenden Studienfragen wurden zwei empirische Studien (Studie 1 und 2) sowie ein systematisches Review (Studie 3) durchgeführt. In Studie 1 und 2 durchliefen Studienteilnehmer mit einer chronischen Aphasie nach einem Schlaganfall ein adaptiertes N-Back-Training. Es zeigte sich ein sehr gemischtes Trainingsmuster und Transfereffekte bei den Studienteilnehmern: Fünf von sechs Probanden verbesserten sich signifikant beim N-Back-Training. Alle sechs Probanden zeigten zudem signifikante weite Transfereffekte auf das auditive Satzverständnis. Darüber hinaus konnte ein weiter Transfereffekt auf die Kommunikationsfähigkeit und das Gedächtnis im Alltag sowie ein naher Transfer auf ungeübte N-Back-Aufgaben nachgewiesen werden. Allerdings schwankte das Transferverhalten innerhalb der Probanden stark. Das systematische Review (Studie 3) zeigte eine schwache interne und externe Validität über die 17 eingeschlossenen Studien. Obwohl die Ergebnisse bezüglich des Arbeitsgedächtnisses, des auditiven Satzverständnisses und des Lesens trotz der methodischen Einschränkungen der untersuchten Studien vielversprechend sind, sollten Schlussfolgerungen über die positiven Transfereffekte von Arbeitsgedächtnistrainings dennoch mit Vorsicht betrachtet werden. Die Ergebnisse der empirischen Studien zeigten, dass sich mit Hilfe eines computergestützten und adaptiven Trainings das Arbeitsgedächtnis verbessert und zudem ein Transfer auf das auditive Satzverständnis und die Kommunikationsfähigkeit im Alltag bei einigen Patienten mit einer chronischen Aphasie nach einem Schlaganfall erzielt werden konnte. Es sind jedoch weitere Studien notwendig, um den Einfluss individueller Unterschiede auf die individuellen Transfermaße aufzudecken und eine Generalisierbarkeit der Ergebnisse auf Untergruppen aphasischer Teilnehmer zu beleuchten. Darüber hinaus werden zukünftige Studien benötigt, die die Rolle der Baseline nicht-linguistischer kognitiver Fähigkeiten und der Sprachproduktion sowie die Aufrechterhaltung von Transfereffekte weiter untersuchen. KW - aphasia KW - working memory KW - treatment KW - Aphasie KW - Arbeitsgedächtnis KW - Therapie Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-423600 ER - TY - JOUR A1 - Zakarias, Lilla A1 - Salis, Christos A1 - Wartenburger, Isabell T1 - Transfer effects on spoken sentence comprehension and functional communication after working memory training in stroke aphasia JF - Journal of neurolinguistics : an international journal for the study of brain function in language behavior and experience N2 - Recent treatment protocols have been successful in improving working memory (WM) in individuals with aphasia. However, the evidence to date is small and the extent to which improvements in trained tasks of WM transfer to untrained memory tasks, spoken sentence comprehension, and functional communication is yet poorly understood. To address these issues, we conducted a multiple baseline study with three German-speaking individuals with chronic post stroke aphasia. Participants practised two computerised WM tasks (n-back with pictures and aback with spoken words) four times a week for a month, targeting two WM processes: updating WM representations and resolving interference. All participants showed improvement on at least one measure of spoken sentence comprehension and everyday memory activities. Two of them showed improvement also on measures of WM and functional communication. Our results suggest that WM can be improved through computerised training in chronic aphasia and this can transfer to spoken sentence comprehension and functional communication in some individuals. KW - Aphasia KW - Working memory KW - n-back training KW - Transfer KW - Sentence comprehension KW - Verbal communication Y1 - 2018 U6 - https://doi.org/10.1016/j.jneuroling.2017.12.002 SN - 0911-6044 VL - 48 SP - 47 EP - 63 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Zabihi, Fatemeh A1 - Graff, Patrick A1 - Schumacher, Fabian A1 - Kleuser, Burkhard A1 - Hedtrich, Sarah A1 - Haag, Rainer T1 - Synthesis of poly(lactide-co-glycerol) as a biodegradable and biocompatible polymer with high loading capacity for dermal drug delivery JF - Nanoscale N2 - Due to the low cutaneous bioavailability of tacrolimus (TAC), penetration enhancers are used to improve its penetration into the skin. However, poor loading capacity, non-biodegradability, toxicity, and in some cases inefficient skin penetration are challenging issues that hamper their applications for the dermal TAC delivery. Here we present poly(lactide-co-glycerol) (PLG) as a water soluble, biodegradable, and biocompatible TAC-carrier with high loading capacity (14.5% w/w for TAC) and high drug delivery efficiencies into the skin. PLG was synthesized by cationic ring-opening copolymerization of a mixture of glycidol and lactide and showed 35 nm and 300 nm average sizes in aqueous solutions before and after loading of TAC, respectively. Delivery experiments on human skin, quantified by fluorescence microscopy and LC-MS/MS, showed a high ability for PLG to deposit Nile red and TAC into the stratum corneum and viable epidermis of skin in comparison with Protopic (R) (0.03% w/w, TAC ointment). The cutaneous distribution profile of delivered TAC proved that 80%, 16%, and 4% of the cutaneous drug level was deposited in the stratum corneum, viable epidermis, and upper dermis, respectively. TAC delivered by PLG was able to efficiently decrease the IL-2 and TSLP expressions in human skin models. Taking advantage of the excellent physicochemical and biological properties of PLG, it can be used for efficient dermal TAC delivery and potential treatment of inflammatory skin diseases. Y1 - 2018 U6 - https://doi.org/10.1039/c8nr05536j SN - 2040-3364 SN - 2040-3372 VL - 10 IS - 35 SP - 16848 EP - 16856 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Yousfi, Alaaeddine A1 - Hewelt, Marcin A1 - Bauer, Christine A1 - Weske, Mathias T1 - Toward uBPMN-Based patterns for modeling ubiquitous business processes JF - IEEE Transactions on Industrial Informatics N2 - Ubiquitous business processes are the new generation of processes that pervade the physical space and interact with their environments using a minimum of human involvement. Although they are now widely deployed in the industry, their deployment is still ad hoc . They are implemented after an arbitrary modeling phase or no modeling phase at all. The absence of a solid modeling phase backing up the implementation generates many loopholes that are stressed in the literature. Here, we tackle the issue of modeling ubiquitous business processes. We propose patterns to represent the recent ubiquitous computing features. These patterns are the outcome of an analysis we conducted in the field of human-computer interaction to examine how the features are actually deployed. The patterns' understandability, ease-of-use, usefulness, and completeness are examined via a user experiment. The results indicate that these four indexes are on the positive track. Hence, the patterns may be the backbone of ubiquitous business process modeling in industrial applications. KW - Ubiquitous business process KW - ubiquitous business process model and notation (uBPMN) KW - ubiquitous business process modeling KW - ubiquitous computing (ubicomp) Y1 - 2017 U6 - https://doi.org/10.1109/TII.2017.2777847 SN - 1551-3203 SN - 1941-0050 VL - 14 IS - 8 SP - 3358 EP - 3367 PB - Inst. of Electr. and Electronics Engineers CY - Piscataway ER - TY - GEN A1 - Young, Linda A1 - Ueda, Kiyoshi A1 - Gühr, Markus A1 - Bucksbaum, Philip H. A1 - Simon, Marc A1 - Mukamel, Shaul A1 - Rohringer, Nina A1 - Prince, Kevin C. A1 - Masciovecchio, Claudio A1 - Meyer, Michael A1 - Rudenko, Artem A1 - Rolles, Daniel A1 - Bostedt, Christoph A1 - Fuchs, Matthias A1 - Reis, David A. A1 - Santra, Robin A1 - Kapteyn, Henry A1 - Murnane, Margaret A1 - Ibrahim, Heide A1 - Légaré, François A1 - Vrakking, Marc A1 - Isinger, Marcus A1 - Kroon, David A1 - Gisselbrecht, Mathieu A1 - L'Huillier, Anne A1 - Wörner, Hans Jakob A1 - Leone, Stephen R. T1 - Roadmap of ultrafast x-ray atomic and molecular physics T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities in the past decade. XFELs now provide unprecedented intensity (1020 W cm−2) of x-rays at wavelengths down to ~1 Ångstrom, and HHG provides unprecedented time resolution (~50 attoseconds) and a correspondingly large coherent bandwidth at longer wavelengths. For context, timescales can be referenced to the Bohr orbital period in hydrogen atom of 150 attoseconds and the hydrogen-molecule vibrational period of 8 femtoseconds; wavelength scales can be referenced to the chemically significant carbon K-edge at a photon energy of ~280 eV (44 Ångstroms) and the bond length in methane of ~1 Ångstrom. With these modern x-ray sources one now has the ability to focus on individual atoms, even when embedded in a complex molecule, and view electronic and nuclear motion on their intrinsic scales (attoseconds and Ångstroms). These sources have enabled coherent diffractive imaging, where one can image non-crystalline objects in three dimensions on ultrafast timescales, potentially with atomic resolution. The unprecedented intensity available with XFELs has opened new fields of multiphoton and nonlinear x-ray physics where behavior of matter under extreme conditions can be explored. The unprecedented time resolution and pulse synchronization provided by HHG sources has kindled fundamental investigations of time delays in photoionization, charge migration in molecules, and dynamics near conical intersections that are foundational to AMO physics and chemistry. This roadmap coincides with the year when three new XFEL facilities, operating at Ångstrom wavelengths, opened for users (European XFEL, Swiss-FEL and PAL-FEL in Korea) almost doubling the present worldwide number of XFELs, and documents the remarkable progress in HHG capabilities since its discovery roughly 30 years ago, showcasing experiments in AMO physics and other applications. Here we capture the perspectives of 17 leading groups and organize the contributions into four categories: ultrafast molecular dynamics, multidimensional x-ray spectroscopies; high-intensity x-ray phenomena; attosecond x-ray science. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 668 KW - ultrafast molecular dynamics KW - x-ray spectroscopies and phenomena KW - table-top sources KW - x-ray free-electron lasers KW - attosecond phenomena Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-424238 SN - 1866-8372 IS - 668 ER - TY - JOUR A1 - Young, Linda A1 - Ueda, Kiyoshi A1 - Gühr, Markus A1 - Bucksbaum, Philip H. A1 - Simon, Marc A1 - Mukamel, Shaul A1 - Rohringer, Nina A1 - Prince, Kevin C. A1 - Masciovecchio, Claudio A1 - Meyer, Michael A1 - Rudenko, Artem A1 - Rolles, Daniel A1 - Bostedt, Christoph A1 - Fuchs, Matthias A1 - Reis, David A. A1 - Santra, Robin A1 - Kapteyn, Henry A1 - Murnane, Margaret A1 - Ibrahim, Heide A1 - Legare, Francois A1 - Vrakking, Marc A1 - Isinger, Marcus A1 - Kroon, David A1 - Gisselbrecht, Mathieu A1 - Wörner, Hans Jakob A1 - Leone, Stephen R. T1 - Roadmap of ultrafast x-ray atomic and molecular physics JF - Journal of physics : B, Atomic, molecular and optical physics N2 - X-ray free-electron lasers (XFELs) and table-top sources of x-rays based upon high harmonic generation (HHG) have revolutionized the field of ultrafast x-ray atomic and molecular physics, largely due to an explosive growth in capabilities in the past decade. XFELs now provide unprecedented intensity (10(20) W cm(-2)) of x-rays at wavelengths down to similar to 1 Angstrom, and HHG provides unprecedented time resolution (similar to 50 attoseconds) and a correspondingly large coherent bandwidth at longer wavelengths. For context, timescales can be referenced to the Bohr orbital period in hydrogen atom of 150 attoseconds and the hydrogen-molecule vibrational period of 8 femtoseconds; wavelength scales can be referenced to the chemically significant carbon K-edge at a photon energy of similar to 280 eV (44 Angstroms) and the bond length in methane of similar to 1 Angstrom. With these modern x-ray sources one now has the ability to focus on individual atoms, even when embedded in a complex molecule, and view electronic and nuclear motion on their intrinsic scales (attoseconds and Angstroms). These sources have enabled coherent diffractive imaging, where one can image non-crystalline objects in three dimensions on ultrafast timescales, potentially with atomic resolution. The unprecedented intensity available with XFELs has opened new fields of multiphoton and nonlinear x-ray physics where behavior of matter under extreme conditions can be explored. The unprecedented time resolution and pulse synchronization provided by HHG sources has kindled fundamental investigations of time delays in photoionization, charge migration in molecules, and dynamics near conical intersections that are foundational to AMO physics and chemistry. This roadmap coincides with the year when three new XFEL facilities, operating at Angstrom wavelengths, opened for users (European XFEL, Swiss-FEL and PAL-FEL in Korea) almost doubling the present worldwide number of XFELs, and documents the remarkable progress in HHG capabilities since its discovery roughly 30 years ago, showcasing experiments in AMO physics and other applications. Here we capture the perspectives of 17 leading groups and organize the contributions into four categories: ultrafast molecular dynamics, multidimensional x-ray spectroscopies; high-intensity x-ray phenomena; attosecond x-ray science. KW - ultrafast molecular dynamics KW - x-ray spectroscopies and phenomena KW - table-top sources KW - x-ray free-electron lasers KW - attosecond phenomena Y1 - 2018 U6 - https://doi.org/10.1088/1361-6455/aa9735 SN - 0953-4075 SN - 1361-6455 VL - 51 IS - 3 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Yilmaz, Zafer T1 - Revising the culture of political protest after the gezi uprising in Turkey BT - radical imagination, affirmative resistance, and the new politics of desire and dignity JF - Mediterranean Quarterly N2 - The Gezi uprising can be considered a crucial turning in Turkish politics. As a response to countrywide democratic protests, the Justice and Development Party (AKP) government revived the security state, escalated authoritarian tendencies, and started to organize a nationalist, Islamist, and conservative backlash. This essay argues that the Gezi Park protests revealed both the fragility of the AKP's hegemony and the limits of the dominant political group habitus, which were promoted by the party to consolidate political polarization in favor of the party's hegemony. Moreover, it is argued that the Gezi uprising transformed the culture of political protests in the country and paved the way for the emergence of affirmative resistance, radical imagination, and a new politics of desire and dignity against authoritarian and neoliberal policies. KW - Erdogan KW - Turkish politics KW - democracy KW - authoritarianism KW - AKP Y1 - 2018 U6 - https://doi.org/10.1215/10474552-7003168 SN - 1047-4552 SN - 1527-1935 VL - 29 IS - 3 SP - 55 EP - 77 PB - Duke Univ. Press CY - Durham ER - TY - JOUR A1 - Yedidya, Asaf T1 - Enlisted History BT - Zeev Jawitz (1847–1924) and the Making of a National Orthodox Wissenschaft des Judentums JF - PaRDES : Zeitschrift der Vereinigung für Jüdische Studien e. V. N2 - Zeev Jawitz (1847–1924) was active in all spheres of culture: history, language, literature and pedagogy, all the while striving for harmonization with the Orthodox outlook. He understood that a people returning to its homeland needed a national culture, one that was both broad and deep, and that the narrow world of the Halakhah would no longer suffice. His main work was the multi-volume Toldot Israel (History of Israel, published 1895–1924) which encompasses Jewish history from its beginning – Patriarchs – until the end of the 19th century. His historical writing, with its emphasis on internal religious Jewish sources, the unity and continuity of Jewish history, and respect of Orthodox principles, comes as an alternative to the historiography of the celebrated historian Heinrich Graetz. The alternative that Jawitz tried to substitute for Wissenschaft des Judentums, was influenced not only by Orthodox ideology, which he supported, but also by his nationalist ideology. He saw himself and his disciples as the “priests of memory,” presenting the true and immanent history and character of the Jewish nation as a platform to the Jewish future in the land of Israel. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-417808 SP - 79 EP - 101 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Ye, Shengyi A1 - Kurth, William S. A1 - Hospodarsky, George B. A1 - Persoon, Ann M. A1 - Sulaiman, Ali H. A1 - Gurnett, Don A. A1 - Morooka, Michiko A1 - Wahlund, Jan-Erik A1 - Hsu, Hsiang-Wen A1 - Sternovsky, Zoltan A1 - Wang, Xu A1 - Horanyi, M. A1 - Seiss, Martin A1 - Srama, Ralf T1 - Dust Observations by the Radio and Plasma Wave Science Instrument During JF - Geophysical research letters N2 - Plain Language Summary Cassini flew through the gap between Saturn and its rings for 22 times before plunging into the atmosphere of Saturn, ending its 20-year mission. The radio and plasma waves instrument on board Cassini helped quantify the dust hazard in this previously unexplored region. The measured density of large dust particles was much lower than expected, allowing high-value science observations during the subsequent Grand Finale orbits. Y1 - 2018 U6 - https://doi.org/10.1029/2018GL078059 SN - 0094-8276 SN - 1944-8007 VL - 45 IS - 19 SP - 10101 EP - 10109 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Ye, S. -Y. A1 - Kurth, William S. A1 - Hospodarsky, George B. A1 - Persoon, Ann M. A1 - Gurnett, Don A. A1 - Morooka, Michiko A1 - Wahlund, Jan-Erik A1 - Hsu, Hsiang-Wen A1 - Seiss, Martin A1 - Srama, Ralf T1 - Cassini RPWS dust observation near the Janus/Epimetheus orbit JF - Journal of geophysical research : Space physics N2 - During the Ring Grazing orbits near the end of Cassini mission, the spacecraft crossed the equatorial plane near the orbit of Janus/Epimetheus (similar to 2.5 Rs). This region is populated with dust particles that can be detected by the Radio and Plasma Wave Science (RPWS) instrument via an electric field antenna signal. Analysis of the voltage waveforms recorded on the RPWS antennas provides estimations of the density and size distribution of the dust particles. Measured RPWS profiles, fitted with Lorentzian functions, are shown to be mostly consistent with the Cosmic Dust Analyzer, the dedicated dust instrument on board Cassini. The thickness of the dusty ring varies between 600 and 1,000 km. The peak location shifts north and south within 100 km of the ring plane, likely a function of the precession phase of Janus orbit. KW - Saturn KW - dust KW - ring Y1 - 2018 U6 - https://doi.org/10.1029/2017JA025112 SN - 2169-9380 SN - 2169-9402 VL - 123 IS - 6 SP - 4952 EP - 4960 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Yazmaciyan, Aren A1 - Stolterfoht, Martin A1 - Burn, Paul L. A1 - Lin, Qianqian A1 - Meredith, Paul A1 - Armin, Ardalan T1 - Recombination losses above and below the transport percolation threshold in bulk heterojunction organic solar cells JF - Advanced energy materials N2 - Achieving the highest power conversion efficiencies in bulk heterojunction organic solar cells requires a morphology that delivers electron and hole percolation pathways for optimized transport, plus sufficient donor:acceptor contact area for near unity charge transfer state formation. This is a significant structural challenge, particularly in semiconducting polymer:fullerene systems. This balancing act in the model high efficiency PTB7:PC70BM blend is studied by tuning the donor:acceptor ratio, with a view to understanding the recombination loss mechanisms above and below the fullerene transport percolation threshold. The internal quantum efficiency is found to be strongly correlated to the slower carrier mobility in agreement with other recent studies. Furthermore, second-order recombination losses dominate the shape of the current density-voltage curve in efficient blend combinations, where the fullerene phase is percolated. However, below the charge transport percolation threshold, there is an electric-field dependence of first-order losses, which includes electric-field-dependent photogeneration. In the intermediate regime, the fill factor appears to be limited by both first- and second-order losses. These findings provide additional basic understanding of the interplay between the bulk heterojunction morphology and the order of recombination in organic solar cells. They also shed light on the limitations of widely used transport models below the percolation threshold. KW - bulk heterojunctions KW - charge transport KW - organic solar cells KW - percolation threshold KW - recombination losses Y1 - 2018 U6 - https://doi.org/10.1002/aenm.201703339 SN - 1614-6832 SN - 1614-6840 VL - 8 IS - 18 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Yarman, Aysu A1 - Kurbanoglu, Sevinc A1 - Jetzschmann, Katharina J. A1 - Ozkan, Sibel A. A1 - Wollenberger, Ulla A1 - Scheller, Frieder W. T1 - Electrochemical MIP-Sensors for Drugs JF - Current Medicinal Chemistry N2 - In order to replace bio-macromolecules by stable synthetic materials in separation techniques and bioanalysis biomimetic receptors and catalysts have been developed: Functional monomers are polymerized together with the target analyte and after template removal cavities are formed in the "molecularly imprinted polymer" (MIP) which resemble the active sites of antibodies and enzymes. Starting almost 80 years ago, around 1,100 papers on MIPs were published in 2016. Electropolymerization allows to deposit MIPs directly on voltammetric electrodes or chips for quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). For the readout of MIPs for drugs amperometry, differential pulse voltammetry (DPV) and impedance spectroscopy (EIS) offer higher sensitivity as compared with QCM or SPR. Application of simple electrochemical devices allows both the reproducible preparation of MIP sensors, but also the sensitive signal generation. Electrochemical MIP-sensors for the whole arsenal of drugs, e.g. the most frequently used analgesics, antibiotics and anticancer drugs have been presented in literature and tested under laboratory conditions. These biomimetic sensors typically have measuring ranges covering the lower nano-up to millimolar concentration range and they are stable under extreme pH and in organic solvents like nonaqueous extracts. KW - Biomimetic sensors KW - molecularly imprinted polymers KW - drug sensors KW - drug imprinting KW - electropolymerization KW - electrochemical sensors Y1 - 2018 U6 - https://doi.org/10.2174/0929867324666171005103712 SN - 0929-8673 SN - 1875-533X VL - 25 IS - 33 SP - 4007 EP - 4019 PB - Bentham Science Publishers LTD CY - Sharjah ER - TY - JOUR A1 - Yarman, Aysu T1 - Electrosynthesized Molecularly Imprinted Polymer for Laccase Using the Inactivated Enzyme as the Target JF - Bulletin of the Korean chemical society N2 - The first molecularly imprinted polymer (MIP) for the recognition of the copper-enzyme laccase was successfully prepared by electropolymerizing scopoletin in the presence of alkaline-inactivated enzyme. Laccase-MIP and the control polymer without laccase (nonimprinted polymer, NIP) were characterized by voltammetry using the redox marker ferricyanide. After electropolymerization, the signals for ferricyanide for both the MIP and the NIP were almost completely suppressed and increased after removal of the target from the polymer layer. Rebinding of both inactivated and active laccase decreased the ferricyanide peak currents to almost equal extent. The relative decrease of signal suppression approached saturation above 10 nM. Furthermore, the surface activity of rebound laccase toward the oxidation of catechol was investigated. The surface activity approached saturation above 10 nM, a value close to the value of the measurements with ferricyanide. Interaction of NIP with laccase brought about a six times smaller signal of catechol oxidation. KW - Molecularly imprinted polymers KW - Biomimetic sensors KW - Laccase KW - Electropolymerization KW - Scopoletin Y1 - 2018 U6 - https://doi.org/10.1002/bkcs.11413 SN - 1229-5949 VL - 39 IS - 4 SP - 483 EP - 488 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Yaouba, Souaibou A1 - Koch, Andreas A1 - Guantai, Eric M. A1 - Derese, Solomon A1 - Irungu, Beatrice A1 - Heydenreich, Matthias A1 - Yenesew, Abiy T1 - Alkenyl cyclohexanone derivatives from Lannea rivae and Lannea schweinfurthii JF - Phytochemistry letters / Phytochemical Society of Europe N2 - Phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Lannea rivae (Chiov) Sacleux (Anacardiaceae) led to the isolation of a new alkenyl cyclohexenone derivative: (4R,6S)-4,6-dihydroxy-6-((Z)-nonadec-14′-en-1-yl)cyclohex-2-en-1-one (1), and a new alkenyl cyclohexanol derivative: (2S*,4R*,5S*)-2,4,5-trihydroxy-2-((Z)-nonadec-14′-en-1-yl)cyclohexanone (2) along with four known compounds, namely epicatechin gallate, taraxerol, taraxerone and β-sitosterol; while the stem bark afforded two known compounds, daucosterol and lupeol. Similar investigation of the roots of Lannea schweinfurthii (Engl.) Engl. led to the isolation of four known compounds: 3-((E)-nonadec-16′-enyl)phenol, 1-((E)-heptadec-14′-enyl)cyclohex-4-ene-1,3-diol, catechin, and 1-((E)-pentadec-12′-enyl)cyclohex-4-ene-1,3-diol. The structures of the isolated compounds were determined by NMR spectroscopy and mass spectrometry. The absolute configuration of compound 1 was established by quantum chemical ECD calculations. In an antibacterial activity assay using the microbroth kinetic method, compound 1 showed moderate activity against Escherichia coli while compound 2 exhibited moderate activity against Staphylococcus aureus. Compound 1 also showed moderate activity against E. coli using the disc diffusion method. The roots extract of L. rivae was notably cytotoxic against both the DU-145 prostate cancer cell line and the Vero mammalian cell line (CC50 = 5.24 and 5.20 μg/mL, respectively). Compound 1 was also strongly cytotoxic against the DU-145 cell line (CC50 = 0.55 μg/mL) but showed no observable cytotoxicity (CC50 > 100 μg/mL) against the Vero cell line. The roots extract of L. rivae and L. schweinfurthii, epicatechin gallate as well as compound 1 exhibited inhibition of carageenan-induced inflammation. KW - Lannea rivae KW - Lannea schweinfurthii KW - Alkenyl cyclohexenone KW - Alkenyl cyclohexanone KW - Anti-inflammatory KW - Cytotoxicity KW - Antimicrobial Y1 - 2017 U6 - https://doi.org/10.1016/j.phytol.2017.12.001 SN - 1874-3900 SN - 1876-7486 VL - 23 SP - 141 EP - 148 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Yannelli, Florencia A. A1 - Karrer, Gerhard A1 - Hall, Rea A1 - Kollmann, Johannes A1 - Heger, Tina T1 - Seed density is more effective than multi-trait limiting similarity in controlling grassland resistance against plant invasions in mesocosms JF - Applied vegetation science : official organ of the International Association for Vegetation Science N2 - QuestionDisturbed areas offer great opportunities for restoring native biodiversity, but they are also prone to invasion by alien plants. Following the limiting similarity hypothesis, we address the question of whether or not similarity of plant functional traits helps developing seed mixtures of native communities with high resistance to invasive species at an early stage of restoration. LocationCentre of Greenhouses and Laboratories Durnast, Technische Universitat Munchen, Freising, Germany. MethodsUsing a system of linear equations, we designed native communities maximizing the similarity between the native and two invasive species according to ten functional traits. We used native grassland plants, two invasive alien species that are often problematic in disturbed areas (i.e., Ambrosia artemisiifolia and Solidago gigantea) and trait information obtained from databases. The two communities were then tested for resistance against establishment of the two invaders separately in a greenhouse experiment. We measured height of the invasive species and above-ground biomass, along with leaf area index, 4 and 8months after sowing respectively. ResultsBoth invasive species were successfully reduced by the native community designed to suppress S. gigantea dominated by small-seeded species. These results could be considered as partial support for the limiting similarity hypothesis. However, given the success of this mixture against both invasive species, suppression was better explained by a seed density effect resulting from the smaller seed mass of the native species included in this mixture. Further, the dominance of a fast-developing competitive species could also contribute to its success. ConclusionsThere was no unequivocal support for the limiting similarity hypothesis in terms of the traits selected. Instead we found that increasing seeding density of native species and selecting species with a fast vegetative development is an effective way to suppress invasive plants during early stages of restoration. If limiting similarity is used to design communities for restoration, early life-history traits should be taken into account. KW - Achillea millefolium KW - Ambrosia artemisiifolia KW - biotic resistance KW - competition KW - density-driven suppression KW - disturbed areas KW - restoration KW - seed mixtures KW - Solidago gigantea Y1 - 2018 U6 - https://doi.org/10.1111/avsc.12373 SN - 1402-2001 SN - 1654-109X VL - 21 IS - 3 SP - 411 EP - 418 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Yang, Jie A1 - Zhu, Xiaolei A1 - Wolf, Thomas J. A. A1 - Li, Zheng A1 - Nunes, João Pedro Figueira A1 - Coffee, Ryan A1 - Cryan, James P. A1 - Gühr, Markus A1 - Hegazy, Kareem A1 - Heinz, Tony F. A1 - Jobe, Keith A1 - Li, Renkai A1 - Shen, Xiaozhe A1 - Veccione, Theodore A1 - Weathersby, Stephen A1 - Wilkin, Kyle J. A1 - Yoneda, Charles A1 - Zheng, Qiang A1 - Martinez, Todd J. A1 - Centurion, Martin A1 - Wang, Xijie T1 - Imaging CF3I conical intersection and photodissociation dynamics with ultrafast electron diffraction JF - Science N2 - Conical intersections play a critical role in excited-state dynamics of polyatomic molecules because they govern the reaction pathways of many nonadiabatic processes. However, ultrafast probes have lacked sufficient spatial resolution to image wave-packet trajectories through these intersections directly. Here, we present the simultaneous experimental characterization of one-photon and two-photon excitation channels in isolated CF3I molecules using ultrafast gas-phase electron diffraction. In the two-photon channel, we have mapped out the real-space trajectories of a coherent nuclear wave packet, which bifurcates onto two potential energy surfaces when passing through a conical intersection. In the one-photon channel, we have resolved excitation of both the umbrella and the breathing vibrational modes in the CF3 fragment in multiple nuclear dimensions. These findings benchmark and validate ab initio nonadiabatic dynamics calculations. Y1 - 2018 U6 - https://doi.org/10.1126/science.aat0049 SN - 0036-8075 SN - 1095-9203 VL - 361 IS - 6397 SP - 64 EP - 67 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - JOUR A1 - Yang, Guang A1 - Hu, Rongting A1 - Ding, Hong-ming A1 - Kochovski, Zdravko A1 - Mei, Shilin A1 - Lu, Yan A1 - Ma, Yu-qiang A1 - Chen, Guosong A1 - Jiang, Ming T1 - CO2-switchable response of protein microtubules BT - behaviour and mechanism JF - Materials chemistry frontiers N2 - Recently, we proposed a small molecular inducing ligand strategy to assemble proteins into highly-ordered structures via dual non-covalent interactions, i.e. carbohydrate-protein interaction and dimerization of Rhodamine B. Using this approach, artificial protein microtubules were successfully constructed. In this study, we find that these microtubules exhibit a perfect CO2 responsiveness; assembly and disassembly of these microtubules were nicely controlled by the alternative passage of CO2 and N-2. Upon the injection of CO2, a negative net-charged SBA turns into a neutral or positive net-charged SBA, which elongated, to some extent, the effective distance between SBA and Rhodamine B, resulting in the disassociation of the Rhodamine B dimer. Further experimental and simulation results reveal that the CO2-responsive mechanism differs from that of solubility change of the previously reported CO2-responsive synthetic materials. Y1 - 2018 U6 - https://doi.org/10.1039/c8qm00245b SN - 2052-1537 VL - 2 IS - 9 SP - 1642 EP - 1646 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Yan, Wan A1 - Rudolph, Tobias A1 - Nöchel, Ulrich A1 - Gould, Oliver E. C. A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Reversible actuation of thermoplastic multiblock copolymers with overlapping thermal transitions of crystalline and glassy domains JF - Macromolecules : a publication of the American Chemical Society N2 - Polymeric materials possessing specific features like programmability, high deformability, and easy processability are highly desirable for creating modern actuating systems. In this study, thermoplastic shape-memory polymer actuators obtained by combining crystallizable poly(epsilon-caprolactone) (PCL) and poly(3S-isobutylmorpholin-2,5-dione) (PIBMD) segments in multiblock copolymers are described. We designed these materials according to our hypothesis that the confinement of glassy PIBMD domains present at the upper actuation temperature contribute to the stability of the actuator skeleton, especially at large programming strains. The copolymers have a phase-segregated morphology, indicated by the well-separated melting and glass transition temperatures for PIBMD and PCL, but possess a partially overlapping T-m of PCL and T-g of PIBMD in the temperature interval from 40 to 60 degrees C. Crystalline PIBMD hard domains act as strong physical netpoints in the PIBMD-PCL bulk material enabling high deformability (up to 2000%) and good elastic recoverability (up to 80% at 50 degrees C above T-m,T-PCL). In the programmed thermoplastic actuators a high content of crystallizable PCL actuation domains ensures pronounced thermoreversible shape changes upon repetitive cooling and heating. The programmed actuator skeleton, composed of PCL crystals present at the upper actuation temperature T-high and the remaining glassy PIBMD domains, enabled oriented crystallization upon cooling. The actuation performance of PIBMD-PCL could be tailored by balancing the interplay between actuation and skeleton, but also by varying the quantity of crystalline PIBMD hard domains via the copolymer composition, the applied programming strain, and the choice of T-high. The actuator with 17 mol% PIBMD showed the highest reversible elongation of 11.4% when programmed to a strain of 900% at 50 degrees C. It is anticipated that the presented thermoplastic actuator materials can be applied as modern compression textiles. Y1 - 2018 U6 - https://doi.org/10.1021/acs.macromol.8b00322 SN - 0024-9297 SN - 1520-5835 VL - 51 IS - 12 SP - 4624 EP - 4632 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Yan, Wan A1 - Fang, Liang A1 - Nöchel, Ulrich A1 - Gould, Oliver E. C. A1 - Behl, Marc A1 - Kratz, Karl A1 - Lendlein, Andreas T1 - Investigating the roles of crystallizable and glassy switching segments within multiblock copolymer shape-memory materials JF - MRS Advances N2 - The variation of the molecular architecture of multiblock copolymers has enabled the introduction of functional behaviour and the control of key mechanical properties. In the current study, we explore the synergistic relationship of two structural components in a shape-memory material formed of a multiblock copolymer with crystallizable poly(epsilon-caprolactone) and crystallizable polyfoligo(3S-iso-butylmorpholine-2,5-dione) segments (PCL-PIBMD). The thermal and structural properties of PCL-PIBMD films were compared with PCI.-PU and PMMD-PU investigated by means of DSC, SAXS and WARS measurements. The shape-memory properties were quantified by cyclic, thermomechanical tensile tests, where deformation strains up to 900% were applied for programming PCL-PIBMD films at 50 degrees C. Toluene vapor treatment experiments demonstrated that the temporary shape was fixed mainly by glassy PIBMD domains at strains lower than 600% with the PCL contribution to fixation increasing to 42 +/- 2% at programming strains of 900% This study into the shape-memory mechanism of PCL-PIBMD provides insight into the structure function relation in multiblock copolymers with both crystallizable and glassy switching segments. Y1 - 2018 U6 - https://doi.org/10.1557/adv.2018.590 SN - 2059-8521 VL - 3 IS - 63 SP - 3741 EP - 3749 PB - Cambridge Univ. Press CY - New York ER - TY - JOUR A1 - Yamazaki, Yosuke A1 - Stolle, Claudia A1 - Matzka, Jürgen A1 - Liu, Huixin A1 - Tao, Chihiro T1 - Interannual variability of the daytime equatorial ionospheric electric field JF - Journal of geophysical research : Space physics N2 - Understanding the variability of the ionosphere is important for the prediction of space weather and climate. Recent studies have shown that forcing from the lower atmosphere plays a significant role for the short-term (day-to-day) variability of the low-latitude ionosphere. The present study aims to assess the importance of atmospheric forcing for the variability of the daytime equatorial ionospheric electric field on the interannual (year-to-year) time scale. Magnetic field measurements from Huancayo (12.05 degrees S, 75.33 degrees W) are used to augment the equatorial vertical plasma drift velocity (V-Z) measurements from the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere radar during 2001-2016. V-Z can be regarded as a measure of the zonal electric field. After removing the seasonal variation of similar to 10m/s, midday values of V-Z show an interannual variation of similar to 2m/s with an oscillation period of 2-3years. No evidence of solar cycle influence is found. The Ground-to-topside Atmosphere-Ionosphere model for Aeronomy, which takes into account realistic atmospheric variability below 30km, reproduces the pattern of the observed interannual variation without having to include variable forcing from the magnetosphere. The results indicate that lower atmospheric forcing plays a dominant role for the observed interannual variability of V-Z at 1200 local time. KW - interannual variability KW - plasma drifts KW - equatorial electrojet (EEJ) KW - vertical coupling KW - JULIA KW - GAIA Y1 - 2018 U6 - https://doi.org/10.1029/2017JA025165 SN - 2169-9380 SN - 2169-9402 VL - 123 IS - 5 SP - 4241 EP - 4256 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Yamazaki, Yosuke A1 - Stolle, Claudia A1 - Matzka, Jürgen A1 - Alken, Patrick T1 - Quasi-6-Day Wave Modulation of the Equatorial Electrojet JF - Journal of geophysical research : Space physics N2 - The equatorial electrojet is an enhanced eastward current in the dayside E region ionosphere flowing along the magnetic equator. The equatorial electrojet is highly variable as it is subject to various forcing mechanisms including atmospheric waves from the lower layers of the atmosphere. There are occasionally times when the intensity of the equatorial electrojet at a fixed longitude shows an oscillatory variation with a period of approximately 6days. We present case studies of such events based on the equatorial electrojet measurements from the CHAMP and Swarm satellites. The spatial and temporal variability of the equatorial electrojet intensity during these events reveals characteristics of a westward propagating wave with zonal wavenumber 1, consistent with the effect of the quasi-6-day planetary wave. Analyses of the geopotential height data from the Aura satellite confirm the presence of the quasi-6-day planetary wave in the lower thermosphere during the events. The amplitude of the quasi-6-day variation in the equatorial electrojet intensity depends on longitude, but no systematic longitudinal dependence is found for different events. During the event of August 2010, quasi-6-day variations are also observed by ground-based magnetometers and a radar in the Peruvian sector. The effect of the quasi-6-day wave accounts for up to +/- 5.9m/s in the equatorial vertical plasma velocity at noon, which is much larger than previously predicted by a numerical model. These results suggest that the quasi-6-day planetary wave is an important source of short-term variability in the equatorial ionosphere. Y1 - 2018 U6 - https://doi.org/10.1029/2018JA025365 SN - 2169-9380 SN - 2169-9402 VL - 123 IS - 5 SP - 4094 EP - 4109 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Yalew, S. G. A1 - Pilz, Tobias A1 - Schweitzer, C. A1 - Liersch, Stefan A1 - van der Kwast, J. A1 - van Griensven, A. A1 - Mul, Marloes L. A1 - Dickens, Chris A1 - van der Zaag, Pieter T1 - Coupling land-use change and hydrologic models for quantification of catchment ecosystem services JF - Environmental modelling & software with environment data news N2 - Representation of land-use and hydrologic interactions in respective models has traditionally been problematic. The use of static land-use in most hydrologic models or that of the use of simple hydrologic proxies in land-use change models call for more integrated approaches. The objective of this study is to assess whether dynamic feedback between land-use change and hydrology can (1) improve model performances, and/or (2) produce a more realistic quantification of ecosystem services. To test this, we coupled a land-use change model and a hydrologic mode. First, the land-use change and the hydrologic models were separately developed and calibrated. Then, the two models were dynamically coupled to exchange data at yearly time-steps. The approach is applied to a catchment in South Africa. Performance of coupled models when compared to the uncoupled models were marginal, but the coupled models excelled at the quantification of catchment ecosystem services more robustly. KW - Model coupling KW - Ecosystem services KW - Integrated modelling KW - Land and water Y1 - 2018 U6 - https://doi.org/10.1016/j.envsoft.2018.08.029 SN - 1364-8152 SN - 1873-6726 VL - 109 SP - 315 EP - 328 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Yalcinkaya, Hacer A1 - Bressel, Katharina A1 - Lindner, Peter A1 - Gradzielski, Michael T1 - Controlled formation of vesicles with added styrene and their fixation by polymerization JF - Journal of colloid and interface science N2 - Hypothesis: An effective way for fixating vesicle structures is the insertion of monomers and cross-linking agents into their bilayer, and their subsequent polymerization can lead to the formation of polymeric nanocapsules. Particularly attractive here are vesicle systems that form spontaneously well-defined small vesicles, as obtaining such small nanocapsules with sizes below 100 nm is still challenging. Experiments: A spontaneously forming well-defined vesicle system composed of the surfactants TDMAO (tetradecyldimethylamine oxide), Pluronic L35, and LiPFOS (lithium perfluorooctylsulfonate) mixture was used as template for fixation by polymerization. Therefore, styrene monomer was incorporated into the vesicle bilayer and ultimately these structures were fixated by UV induced radical polymerization. Structural alteration of the vesicles upon loading with monomer and the cross-linker as well as the effect of subsequent polymerization in the membrane were investigated in detail by turbidity measurements, dynamic and static light scattering, (DLS, SLS), and small angle neutron scattering (SANS). Findings: The analysis showed the changes on vesicle structures due to the monomer loading, and that these structures can become permanently fixed by the polymerization process. The potential of this approach to produce well-defined nanocapsules starting from a self-assembled system and following polymerization is critically evaluated. (C) 2018 Elsevier Inc. All rights reserved. KW - Template reaction KW - Zwitterionic surfactant KW - Anionic surfactant KW - Styrene KW - Vesicle KW - Small angle neutron scattering KW - Polymerization Y1 - 2018 U6 - https://doi.org/10.1016/j.jcis.2018.07.097 SN - 0021-9797 SN - 1095-7103 VL - 531 SP - 672 EP - 680 PB - Elsevier CY - San Diego ER - TY - GEN A1 - Yadavalli, Nataraja Sekhar A1 - Loebner, Sarah A1 - Papke, Thomas A1 - Sava, Elena A1 - Hurduc, Nicolae A1 - Santer, Svetlana T1 - A comparative study of photoinduced deformation in azobenzene containing polymer films T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In this paper two groups supporting different views on the mechanism of light induced polymer deformation argue about the respective underlying theoretical conceptions, in order to bring this interesting debate to the attention of the scientific community. The group of Prof. Nicolae Hurduc supports the model claiming that the cyclic isomerization of azobenzenes may cause an athermal transition of the glassy azobenzene containing polymer into a fluid state, the so-called photo-fluidization concept. This concept is quite convenient for an intuitive understanding of the deformation process as an anisotropic flow of the polymer material. The group of Prof. Svetlana Santer supports the re-orientational model where the mass-transport of the polymer material accomplished during polymer deformation is stated to be generated by the light-induced re-orientation of the azobenzene side chains and as a consequence of the polymer backbone that in turn results in local mechanical stress, which is enough to irreversibly deform an azobenzene containing material even in the glassy state. For the debate we chose three polymers differing in the glass transition temperature, 32 °C, 87 °C and 95 °C, representing extreme cases of flexible and rigid materials. Polymer film deformation occurring during irradiation with different interference patterns is recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the kinetics of film deformation. We also demonstrated the unique behaviour of azobenzene containing polymeric films to switch the topography in situ and reversibly by changing the irradiation conditions. We discuss the results of reversible deformation of three polymers induced by irradiation with intensity (IIP) and polarization (PIP) interference patterns, and the light of homogeneous intensity in terms of two approaches: the re-orientational and the photo-fluidization concepts. Both agree in that the formation of opto-mechanically induced stresses is a necessary prerequisite for the process of deformation. Using this argument, the deformation process can be characterized either as a flow or mass transport. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 458 KW - light-induced deformation KW - surface-relief gratings KW - optical near-field KW - chromophore orientations KW - atomic-force; nano-objects KW - brushes KW - raman KW - elastomers KW - microscopy Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413510 SN - 1866-8372 IS - 458 ER - TY - JOUR A1 - Xu, Xiao A1 - Angioletti-Uberti, Stefano A1 - Lu, Yan A1 - Dzubiella, Joachim A1 - Ballauff, Matthias T1 - Interaction of Proteins with Polyelectrolytes BT - Comparison of Theory to Experiment JF - Langmuir N2 - We discuss recent investigations of the interaction of polyelectrolytes with proteins. In particular, we review our recent studies on the interaction of simple proteins such as human serum albumin (HSA) and lysozyme with linear polyelectrolytes, charged dendrimers, charged networks, and polyelectrolyte brushes. In all cases discussed here, we combined experimental work with molecular dynamics (MD) simulations and mean-field theories. In particular, isothermal titration calorimetry (ITC) has been employed to obtain the respective binding constants K-b and the Gibbs free energy of binding. MD simulations with explicit counterions but implicit water demonstrate that counterion release is the main driving force for the binding of proteins to strongly charged polyelectrolytes: patches of positive charges located on the surface of the protein become multivalent counterions of the polyelectrolyte, thereby releasing a number of counterions condensed on the polyelectrolyte. The binding Gibbs free energy due to counterion release is predicted to scale with the logarithm of the salt concentration in the system, which is verified by both simulations and experiment. In several cases, namely, for the interaction of proteins with linear polyelectrolytes and highly charged hydrophilic dendrimers, the binding constant could be calculated from simulations to very good approximation. This finding demonstrated that in these cases explicit hydration effects do not contribute to the Gibbs free energy of binding. The Gibbs free energy can also be used to predict the kinetics of protein uptake by microgels for a given system by applying dynamic density functional theory. The entire discussion demonstrates that the direct comparison of theory with experiments can lead to a full understanding of the interaction of proteins with charged polymers. Possible implications for applications, such as drug design, are discussed. Y1 - 2018 U6 - https://doi.org/10.1021/acs.langmuir.8b01802 SN - 0743-7463 VL - 35 IS - 16 SP - 5373 EP - 5391 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Xiong, Tao A1 - Włodarczyk, Radosław Stanisław A1 - Gallandi, Lukas A1 - Körzdörfer, Thomas A1 - Saalfrank, Peter T1 - Vibrationally resolved photoelectron spectra of lower diamondoids BT - a time-dependent approach JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistry N2 - Vibrationally resolved lowest-energy bands of the photoelectron spectra (PES) of adamantane, diamantane, and urotropine were simulated by a time-dependent correlation function approach within the harmonic approximation. Geometries and normal modes for neutral and cationic molecules were obtained from B3LYP hybrid density functional theory (DFT). It is shown that the simulated spectra reproduce the experimentally observed vibrational finestructure (or its absence) quite well. Origins of the finestructure are discussed and related to recurrences of autocorrelation functions and dominant vibrations. Remaining quantitative and qualitative errors of the DFT-derived PES spectra refer to (i) an overall redshift by ∼0.5 eV and (ii) the absence of satellites in the high-energy region of the spectra. The former error is shown to be due to the neglect of many-body corrections to ordinary Kohn-Sham methods, while the latter has been argued to be due to electron-nuclear couplings beyond the Born-Oppenheimer approximation [Gali et al., Nat. Commun. 7, 11327 (2016)]. Y1 - 2018 U6 - https://doi.org/10.1063/1.5012131 SN - 0021-9606 SN - 1089-7690 VL - 148 IS - 4 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Xiong, Tao A1 - Wlodarczyk, Radoslaw A1 - Saalfrank, Peter T1 - Vibrationally resolved absorption and fluorescence spectra of perylene and N-substituted derivatives from autocorrelation function approaches JF - Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature N2 - Vibrationally resolved absorption and emission (fluorescence) spectra of perylene and its N-derivatives in gas phase and in solution (acetonitrile) were simulated using a time-dependent approach based on correlation functions determined by density functional theory. By systematically varying the number and position of N atoms, it is shown that the presence of nitrogen heteroatoms has a negligible effect on the molecular structure and geometric distortions upon electronic transitions, while spectral properties change: in particular the number of N atoms is important while their position is less decisive. Thus, the N-substitution can be used to fine-tune the optical properties of perylene-based molecules. KW - Perylene KW - Vibronic spectrum KW - Correlation function KW - Dimer KW - Excimer KW - PCM Y1 - 2018 U6 - https://doi.org/10.1016/j.chemphys.2018.06.011 SN - 0301-0104 SN - 1873-4421 VL - 515 SP - 728 EP - 736 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Xiong, Tao T1 - Vibrationally resolved absorption, emission, resonance Raman and photoelectron spectra of selected organic molecules, associated radicals and cations T1 - Schwingungsaufgelöste Absorptions-, Emissions-, Resonanz-Raman- und Photoelektronenspektren ausgewählter organischer Moleküle, assoziierter Radikale und Kationen BT - a time-dependent approach BT - ein zeitabhängiger Ansatz N2 - Time-dependent correlation function based methods to study optical spectroscopy involving electronic transitions can be traced back to the work of Heller and coworkers. This intuitive methodology can be expected to be computationally efficient and is applied in the current work to study the vibronic absorption, emission, and resonance Raman spectra of selected organic molecules. Besides, the "non-standard" application of this approach to photoionization processes is also explored. The application section consists of four chapters as described below. In Chapter 4, the molar absorptivities and vibronic absorption/emission spectra of perylene and several of its N-substituted derivatives are investigated. By systematically varying the number and position of N atoms, it is shown that the presence of nitrogen heteroatoms has a negligible effect on the molecular structure and geometric distortions upon electronic transitions, while spectral properties are more sensitive: In particular the number of N atoms is important while their position is less decisive. Thus, N-substitution can be used to fine-tune the optical properties of perylene-based molecules. In Chapter 5, the same methods are applied to study the vibronic absorption/emission and resonance Raman spectra of a newly synthesized donor-acceptor type molecule. The simulated absorption/emission spectra agree fairly well with experimental data, with discrepancies being attributed to solvent effects. Possible modes which may dominate the fine-structure in the vibronic spectra are proposed by analyzing the correlation function with the aid of Raman and resonance Raman spectra. In the next two chapters, besides the above types of spectra, the methods are extended to study photoelectron spectra of several small diamondoid-related systems (molecules, radicals, and cations). Comparison of the photoelectron spectra with available experimental data suggests that the correlation function based approach can describe ionization processes reasonably well. Some of these systems, cationic species in particular, exhibit somewhat peculiar optical behavior, which presents them as possible candidates for functional devices. Correlation function based methods in a more general sense can be very versatile. In fact, besides the above radiative processes, formulas for non-radiative processes such as internal conversion have been derived in literature. Further implementation of the available methods is among our next goals. N2 - Molekülsysteme bestehen aus Kernen und Elektronen, deren viel kleinere Masse sie in die Lage versetzten, sich der Bewegung des ersteren augenblicklich anzupassen. Daher ist die Bewegung der Elektronen und Kerne in einer guten ersten Annäherung "unabhängig", und die Energie der Elektronen kann zuerst berechnet werden, vorausgesetzt, die Kerne sind stationär. Die so gewonnene elektronische Energie wird zur Abstoßungsenergie zwischen den Kernen addiert, um ein Potential zu erhalten, das die Bewegung der Kerne bestimmt. Quantenmechanisch können sowohl die Elektronen als auch die Kerne nur bestimmte Energieniveaus haben. Die molekulare vibronische (= Schwingung + Elektronik) Absorptionsspektroskopie beinhaltet den Übergang der Elektronen und Kerne von ihrem Anfangs- in ihren Endzustand durch Photonenabsorption. Die größere elektronische Übergangsenergie bestimmt die Position des Absorptionsmaximums, während die kleinere nukleare Schwingungsübergangsenergie (ohne Berücksichtigung von Translation und Rotation) die Position der Teilmaxima innerhalb des Absorptionsbereichs bestimmt, wodurch die vibronische Feinstruktur entsteht. Ähnliche Ideen gelten auch für die vibronische Emissionsspektroskopie. Die Resonanz-Raman-Spektroskopie untersucht die Energieänderung des einfallenden Photons (dessen Energie ausreichend ist, um die Elektronen in einen höheren elektronischen Zustand anzuregen), nachdem es mit dem Molekül wechselwirkt. Der Energiegewinn oder -verlust des einfallenden Photons bewirkt eine Änderung des Schwingungszustandes. Die Photoelektronenspektroskopie ist ähnlich wie die vibronische Absorption, benötigt aber in der Regel mehr Energie des einfallenden Photons, da neben der Anregung des Moleküls in einen höheren vibronischen Zustand zusätzliche Energie benötigt wird, um ein Elektron aus dem Molekül zu entfernen. Diese spektroskopischen Techniken liefern wertvolle Informationen über die elektronische und nukleare Bewegung des Moleküls. Theoretisch können wir eine zeitabhängige Korrelationsfunktion verwenden, um die Spektren zu simulieren. Die Korrelationsfunktion für die Absorption ist beispielsweise eine Funktion der Zeit, deren Entwicklung Informationen über die elektronischen Energien und die nukleare Bewegung enthält. Um das Absorptionsspektrum in Form von Energie zu erhalten, wird ein mathematisches Verfahren, die so genannte Fourier-Transformation, auf die zeitabhängige Korrelationsfunktion angewendet, um ein energieabhängiges Spektrum zu erhalten. Diese Methode wird auf ausgewählte organische Moleküle, darunter einige Radikale und Kationen, angewandt, um deren elektronisches und optisches Verhalten unter dem Einfluss von einfallendem Licht zu untersuchen und Einblicke in das Design neuer optoelektronischer Bauelemente zu gewinnen. Bei einigen Molekülen/Systemen wird die vibronische Feinstruktur durch Faktoren wie molekulare Zusammensetzung und Umgebung wie Lösungsmittel beeinflusst, was darauf hindeutet, dass diese Systeme zur Feinabstimmung der gewünschten Eigenschaften verwendet werden können. Für andere Systeme gibt es fast keine sichtbare vibronische Feinstruktur, was bedeutet, dass sich die nukleare Bewegung solcher Systeme im Allgemeinen von derjenigen der vorherigen Kategorie unterscheidet. KW - vibrationally resolved electronic spectroscopy KW - photoelectron spectroscopy KW - resonance Raman spectroscopy KW - correlation function KW - ionization potential KW - time-dependent density functional theory KW - perylene KW - diamondoid KW - Schwingungsaufgelöste UV/VIS-Spektroskopie KW - Photoelektronenspektroskopie KW - Resonanz-Raman-Spektroskopie KW - Korrelationsfunktion KW - Ionisationspotential KW - Zeitabhängige Dichtefunktionaltheorie KW - Perylen KW - Diamondoide Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-418105 ER - TY - JOUR A1 - Xiong, Hui A1 - Fang, Li A1 - Osipov, Timur A1 - Kling, Nora G. A1 - Wolf, Thomas J. A. A1 - Sistrunk, Emily A1 - Obaid, Razib A1 - Gühr, Markus A1 - Berrah, Nora T1 - Fragmentation of endohedral fullerene Ho3N@C-80 in an intense femtosecond near-infrared laser field JF - Physical review : A, Atomic, molecular, and optical physics N2 - The fragmentation of gas phase endohedral fullerene, Ho3N@C-80, was investigated using femtosecond near-infrared laser pulses with an ion velocity map imaging spectrometer. We observed that Ho+ abundance associated with carbon cage opening dominates at an intensity of 1.1 x 10(14) W/cm(2). As the intensity increases, the Ho+ yield associated with multifragmentation of the carbon cage exceeds the prominence of Ho+ associated with the gentler carbon cage opening. Moreover, the power law dependence of Ho+ on laser intensity indicates that the transition of the most likely fragmentation mechanisms occurs around 2.0 x 10(14) W/cm(2). Y1 - 2018 U6 - https://doi.org/10.1103/PhysRevA.97.023419 SN - 2469-9926 SN - 2469-9934 VL - 97 IS - 2 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Xiong, Chao A1 - Stolle, Claudia A1 - Park, Jaeheung T1 - Climatology of GPS signal loss observed by Swarm satellites JF - Annales geophysicae N2 - By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between +/- 5 and +/- 20 degrees magnetic latitude (MLAT) and high latitudes above 60 degrees MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20 degrees, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver. KW - Ionosphere KW - equatorial ionosphere KW - ionospheric irregularities KW - radio science KW - radio wave propagation Y1 - 2018 U6 - https://doi.org/10.5194/angeo-36-679-2018 SN - 0992-7689 SN - 1432-0576 VL - 36 IS - 2 SP - 679 EP - 693 PB - Copernicus CY - Göttingen ER - TY - GEN A1 - Xiong, Chao A1 - Stolle, Claudia A1 - Park, Jaeheung T1 - Climatology of GPS signal loss observed by Swarm satellites T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - By using 3-year global positioning system (GPS)measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20 ◦ magnetic latitude (MLAT) and high latitudes above 60 ◦ MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20 ◦ , and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 712 KW - Ionosphere (equatorial ionosphere; ionospheric irregularities) KW - radio science (radio wave propagation) Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427391 SN - 1866-8372 IS - 712 ER - TY - JOUR A1 - Xiang, Zairong T1 - Transdualism BT - toward a materio-discursive embodiment JF - TSQ-Transgender studies quarterly N2 - The author introduces the concept of transdualism to critique dualism without relying on a dualistic model of critique, the modus operandi necessary for a critique against sexual dualism and hetero/cisnormativity. Transdualism offers an opportunity to dwell within that operation by staying below (not beyond) the “dualism,” that is, below the logic of either/or. The essay will explore the notion of “transdualism” through the hexagram Tai of the Yi Jing, which is often used in medical contexts to illustrate the body-of-orifices of Huangdi Neijing or the Inner Canon of the Yellow Emperor. The author reads this body-of-orifices, which is primarily represented by its nine major bodily tunnels, with yinyang philosophy as gender/sex indeterminant and shows that the Inner Canon's yinyang body-of-orifices points to something more transgressive, which could unsettle from within the naturalism of gender and sexual dualism and the nature/culture as well as other dualistic divides that have informed contemporary critical rethinking of embodiment. By unpacking the hexagram Tai alongside Inner Canon's body-of-orifices. as well as contemporary feminist, queer, and transgender theorizations of the body and sexuality, this essay aims at rethinking the materio-discursive complexity of the body-of-orifices, which has been either dualistically separated into antagonisms between man and woman, sex and gender, body and discourse, yin and yang; or one-sidedly reduced to a function of “social construction,” knowable only through language—or problematically lumped together in a gender-is-fluid postmodern “both-and,” which supposedly overcomes the metaphysico-theological “either/or.” KW - yinyang KW - dualism KW - embodiment KW - either/or KW - Yi Jing (I Ching) Y1 - 2018 U6 - https://doi.org/10.1215/23289252-6900795 SN - 2328-9252 SN - 2328-9260 VL - 5 IS - 3 SP - 425 EP - 442 PB - Duke Univ. Press CY - Durham ER - TY - JOUR A1 - Wörner, Gerhard A1 - Schildgen, Taylor F. A1 - Reich, Martin T1 - The central Andes BT - elements of an extreme land JF - Elements : an international magazine of mineralogy, geochemistry, and petrology N2 - The Central Andes and the Atacama Desert represent a unique geological, climatic, and magmatic setting on our planet. It is the only place on Earth where subduction of an oceanic plate below an active continental margin has led to an extensive mountain chain and an orogenic plateau that is second in size only to the Tibetan Plateau, which resulted from continental collision. In this article, we introduce the history of the Central Andes and the evolution of its landscape. We also discuss links between tectonic forces, magmatism, and the extreme hyperarid climate of this land that, in turn, has led to rich deposits of precious ores and minerals. KW - volcanism KW - active continental margin KW - tectonic shortening KW - uplift and erosion KW - hyperaridity KW - mineral deposits Y1 - 2018 U6 - https://doi.org/10.2138/gselements.14.4.225 SN - 1811-5209 SN - 1811-5217 VL - 14 IS - 4 SP - 225 EP - 230 PB - Mineralogical Society of America CY - Chantilly ER - TY - JOUR A1 - Wyrwa, Ulrich T1 - Rezension zu: Enzyklopädie jüdischer Geschichte und Kultur, ed. Dan Diner, Sächsische Akademie der Wissenschaften zu Leipzig, (Stuttgart –Weimar: Metzler, 2011-2017), 7 Vol T1 - Encyclopedia of Jewish History and Culture JF - Quest-Issues in Contemporary Jewish History Y1 - 2018 U6 - https://doi.org/10.48248/issn.2037-741X/682 SN - 2037-741X VL - 2018 IS - 14 SP - 123 EP - 131 PB - Fondazione Centro Documentazione Ebraica Contemporanea CY - Milano ER - TY - JOUR A1 - Wutke, Saskia A1 - Sandoval-Castellanos, Edson A1 - Benecke, Norbert A1 - Döhle, Hans-Jürgen A1 - Friederich, Susanne A1 - Gonzalez, Javier A1 - Hofreiter, Michael A1 - Lougas, Lembi A1 - Magnell, Ola A1 - Malaspinas, Anna-Sapfo A1 - Morales-Muniz, Arturo A1 - Orlando, Ludovic A1 - Reissmann, Monika A1 - Trinks, Alexandra A1 - Ludwig, Arne T1 - Decline of genetic diversity in ancient domestic stallions in Europe JF - Science Advances N2 - Present-day domestic horses are immensely diverse in their maternally inherited mitochondrial DNA, yet they show very little variation on their paternally inherited Y chromosome. Although it has recently been shown that Y chromosomal diversity in domestic horses was higher at least until the Iron Age, when and why this diversity disappeared remain controversial questions. We genotyped 16 recently discovered Y chromosomal single-nucleotide polymorphisms in 96 ancient Eurasian stallions spanning the early domestication stages (Copper and Bronze Age) to the Middle Ages. Using this Y chromosomal time series, which covers nearly the entire history of horse domestication, we reveal how Y chromosomal diversity changed over time. Our results also show that the lack of multiple stallion lineages in the extant domestic population is caused by neither a founder effect nor random demographic effects but instead is the result of artificial selection-initially during the Iron Age by nomadic people from the Eurasian steppes and later during the Roman period. Moreover, the modern domestic haplotype probably derived from another, already advantageous, haplotype, most likely after the beginning of the domestication. In line with recent findings indicating that the Przewalski and domestic horse lineages remained connected by gene flow after they diverged about 45,000 years ago, we present evidence for Y chromosomal introgression of Przewalski horses into the gene pool of European domestic horses at least until medieval times. Y1 - 2018 U6 - https://doi.org/10.1126/sciadv.aap9691 SN - 2375-2548 VL - 4 IS - 4 PB - American Assoc. for the Advancement of Science CY - Washington ER - TY - JOUR A1 - Wuster, Wolfgang A1 - Chirio, Laurent A1 - Trape, Jean-Francois A1 - Ineich, Ivan A1 - Jackson, Kate A1 - Greenbaum, Eli A1 - Barron, Cesar A1 - Kusamba, Chifundera A1 - Nagy, Zoltan T. A1 - Storey, Richard A1 - Hall, Cara A1 - Wuster, Catharine E. A1 - Barlow, Axel A1 - Broadley, Donald G. T1 - Integration of nuclear and mitochondrial gene sequences and morphology reveals unexpected diversity in the forest cobra (Naja melanoleuca) species complex in Central and West Africa (Serpentes: Elapidae) JF - Zootaxa : an international journal of zootaxonomy ; a rapid international journal for animal taxonomists N2 - Cobras are among the most widely known venomous snakes, and yet their taxonomy remains incompletely understood, particularly in Africa. Here, we use a combination of mitochondrial and nuclear gene sequences and morphological data to diagnose species limits within the African forest cobra, Naja (Boulengerina) melanoleuca. Mitochondrial DNA sequences reveal deep divergences within this taxon. Congruent patterns of variation in mtDNA, nuclear genes and morphology support the recognition of five separate species, confirming the species status of N. subfulva and N. peroescobari, and revealing two previously unnamed West African species, which are described as new: Naja (Boulengerina) guineensis sp. nov. Broadley, Trape, Chirio, Ineich & Wuster, from the Upper Guinea forest of West Africa, and Naja (Boulengerina) savannula sp. nov. Broadley, Trape, Chirio & Wuster, a banded form from the savanna-forest mosaic of the Guinea and Sudanian savannas of West Africa. The discovery of cryptic diversity in this iconic group highlights our limited understanding of tropical African biodiversity, hindering our ability to conserve it effectively. KW - Integrative taxonomy KW - Africa KW - Naja melanoleuca KW - Naja guineensis sp nov. KW - Naja savannula sp nov. KW - Elapidae KW - systematics Y1 - 2018 U6 - https://doi.org/10.11646/zootaxa.4455.1.3 SN - 1175-5326 SN - 1175-5334 VL - 4455 IS - 1 SP - 68 EP - 98 PB - Magnolia Press CY - Auckland ER - TY - JOUR A1 - Wunder, Bernd A1 - Kutzschbach, Martin A1 - Hosse, Luisa A1 - Wilke, Franziska Daniela Helena A1 - Schertl, Hans-Peter A1 - Chopin, Christian T1 - Synthetic B-[4]-bearing dumortierite and natural B-[4]-free magnesiodumortierite from the Dora-Maira Massif BT - differences in boron coordination in response to ultrahigh pressure JF - European journal of mineralogy N2 - Dumortierite was synthesized in piston-cylinder experiments at 2.5-4.0 GPa, 650-700 degrees C in the Al2O3 -B2O3-SiO2-H2O (ABSH) system. Electron-microprobe (EMP) analyses reveal significant boron-excess (up to 0.26 B-[4] per formula unit, pfu) and silicon-deficiency relative to the ideal anhydrous dumortierite stoichiometry Al7BSi3O18 . The EMP data in conjunction with results from single-crystal Raman spectroscopy and powder X-ray diffraction provide evidence that silicon at the tetrahedral site is replaced by excess boron via the substitution Si-[4] <--> B-[4] + H. The Raman spectrum of synthetic dumortierite in the frequency region 2000 4000 cm(-1) comprises eight bands, of which six are located at frequencies below 3400 cm(-1). This points to strong hydrogen bonding, most likely O2-H center dot center dot center dot O7 and O7-H center dot center dot center dot O2, arising from a high number of octahedral vacancies at the All site and substitution of trivalent Al3+ and B3+ for Si4+ at Si1 and Si2 sites, causing decreasing acceptor-donor distances and lower incident valence at the acceptor oxygen. Contrary to the synthetic high-pressure ABSH-dumortierite, magnesiodumortierite from the Dora-Maira Massif, which is assumed to have formed at similar conditions (2.5-3.0 GPa, 700 degrees C), does not show any B-excess. Tourmaline shows an analogous behaviour in that magnesium-rich (e.g., dravitic) tourmaline formed at high pressure shows no or only minor amounts of tetrahedral boron, whereas natural aluminum-rich tourmaline and synthetic olenitic tourmaline formed at high pressures can incorporate significant amounts of tetrahedral boron. Two mechanisms might account for this discrepancy: (i) Structural avoidance of Mg-[6]-(OR3+)-R-[4] configurations in magnesiodumortierite due to charge deficieny at the oxygens O2 and O7 and strong local distortion of M1 due to decreased O2-O7 bond length, and/or (ii) decreasing fluid mobility of boron in Al-rich systems at high pressures. KW - dumortierite KW - magnesiodumortierite KW - Dora-Maira KW - ultrahigh-pressure (UHP) KW - ABSH-system KW - synthesis KW - tetrahedral boron KW - Raman spectroscopy Y1 - 2018 U6 - https://doi.org/10.1127/ejm/2018/0030-2742 SN - 0935-1221 SN - 1617-4011 VL - 30 IS - 3 SP - 471 EP - 483 PB - Schweizerbart CY - Stuttgart ER - TY - THES A1 - Wulff, Alexander T1 - Essays in macroeconomics and financial market imperfections N2 - This dissertation consists of four self-contained papers that deal with the implications of financial market imperfections and heterogeneity. The analysis mainly relates to the class of incomplete-markets models but covers different research topics. The first paper deals with the distributional effects of financial integration for developing countries. Based on a simple heterogeneous-agent approach, it is shown that capital owners experience large welfare losses while only workers moderately gain due to higher wages. The large welfare losses for capital owners contrast with the small average welfare gains from representative-agent economies and indicate that a strong opposition against capital market opening has to be expected. The second paper considers the puzzling observation of capital flows from poor to rich countries and the accompanying changes in domestic economic development. Motivated by the mixed results from the literature, we employ an incomplete-markets model with different types of idiosyncratic risk and borrowing constraints. Based on different scenarios, we analyze under what conditions the presence of financial market imperfections contributes to explain the empirical findings and how the conditions may change with different model assumptions. The third paper deals with the interplay of incomplete information and financial market imperfections in an incomplete-markets economy. In particular, it analyzes the impact of incomplete information about idiosyncratic income shocks on aggregate saving. The results show that the effect of incomplete information is not only quantitatively substantial but also qualitatively ambiguous and varies with the influence of the income risk and the borrowing constraint. Finally, the fourth paper analyzes the influence of different types of fiscal rules on the response of key macroeconomic variables to a government spending shock. We find that a strong temporary increase in public debt contributes to stabilizing consumption and leisure in the first periods following the change in government spending, whereas a non-debt-intensive fiscal rule leads to a faster recovery of consumption, leisure, capital and output in later periods. Regarding optimal debt policy, we find that a debt-intensive fiscal rule leads to the largest aggregate welfare benefit and that the individual welfare gain is particularly high for wealth-poor agents. N2 - Die vorliegende Dissertation besteht aus vier eigenständigen Papieren, die sich mit den Auswirkungen von Finanzmarktunvollkommenheiten und Heterogenität beschäftigen. Die Analyse bezieht sich dabei vorwiegend auf die Klasse heterogener-Agenten Modelle mit Finanzmarktunvollkommenheiten, greift aber verschiedene Fragestellungen auf. Das erste Papier beschäftigt sich mit den Verteilungseffekten finanzieller Integration in sich entwickelnden Volkswirtschaften. Mit Hilfe eines einfachen heterogene-Agenten Ansatzes wird gezeigt, dass inländische Kapitalbesitzer massiv durch finanzielle Integration verlieren, während ausschließlich Arbeitnehmer moderat durch Lohnanstiege gewinnen. Die erheblichen Wohlfahrtsverluste für Kapitalbesitzer stehen dabei im Kontrast zu den geringen durchschnittlichen Wohlfahrtseffekten und zeigen, dass eine starke Opposition gegenüber der Öffnung von Kapitalmärkten in sich entwickelnde Länder zu erwarten ist. Der zweite Aufsatz beschäftigt sich mit dem neueren Phänomen von Kapitalflüssen von armen zu reichen Ländern sowie mit den einhergehenden inländischen Entwicklungen. Ausgehend von den stark divergierenden Ergebnissen der Literatur wird ein umfassendes heterogene-Agenten Modell mit nicht versicherbaren idiosynkratischen Risiken und Verschuldungsrestriktionen betrachtet. Anhand verschiedener Szenarien wird gezeigt, unter welchen Bedingungen Finanzmarktunvollkommenheiten zur Klärung der empirischen Befunde beitragen können und inwiefern sich die Parameterrestriktionen unter verschiedenen Modellannahmen ändern. Der dritte Aufsatz beschäftigt sich mit den Auswirkungen unvollständiger Informationen im Rahmen eines heterogene-Agenten Modells. Insbesondere werden die Auswirkungen unvollständiger Informationen bezüglich idiosynkratischer Einkommensschocks auf die aggregierte Ersparnisbildung untersucht. Die Ergebnisse zeigen, dass der Einfluss unvollständiger Information nicht nur quantitativ bedeutsam, sondern auch qualitativ verschieden ist und stark mit der konkreten Ausprägung der Finanzmarktunvollkommenheiten variiert. Der vierte Aufsatz beschäftigt sich mit der Ausgestaltung staatlicher Verschuldungspolitik. Insbesondere wird die Finanzierung einer vorübergehenden Erhöhung von Staatsausgaben unter verschiedenen Fiskalregeln analysiert. Die Ergebnisse zeigen, dass eine verschuldungsintensive Fiskalregel einen kurzfristig stabilisierenden Effekt auf Konsum und Freizeit aufweist, von dem insbesondere vermögensarme Haushalte profitieren, die besonders stark von den Verschuldungsrestriktionen betroffen sind. KW - incomplete markets KW - heterogeneous agents KW - financial integration KW - incomplete information KW - fiscal policy KW - unvollständige Märkte KW - heterogene Agenten KW - finanzielle Integration KW - unvollständige Information KW - Fiskalpolitik Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-429956 ER - TY - JOUR A1 - Wuertz-Kozak, Karin A1 - Bleisch, Dominique A1 - Nadi, Najia A1 - Proemmel, Peter A1 - Hitzl, Wolfgang A1 - Kessler, Thomas M. M. A1 - Gautschi, Oliver P. A1 - Hausmann, Oliver N. T1 - Sexual and urinary function following anterior lumbar surgery in females JF - Neurourology and urodynamics N2 - Aims Anterior lumbar interbody fusion procedures (ALIF) and total disc replacement (TDR) with anterior exposure of the lumbar spine entail a risk of a vascular injury and dysfunction of the sympathetic and parasympathetic nerves due to disturbance of the inferior and superior hypogastric plexus. While retrograde ejaculation is a known complication of the anterior spinal approach in males, post-operative sexual as well as urinary function in females has not yet been thoroughly investigated and was hence the aim of this study. Methods Fifteen female patients documented their sexual and urinary function preoperatively, 3 months and 6 months postoperatively, using the validated questionnaires FSFI (Female Sexual Function Index) and ICIQ (International Consultation of Incontinence Questionnaire). Randomization tests were used to statistically analyze expectation values over time (two-sided, P < 0.05). Results While no statistically significant change in the total FSFI score occurred over time, a significant increase in FSFI desire score was noted between preoperative (2.95 +/- 0.8) and 6 months follow-up (3.51 +/- 0.6, P = 0.02). Urinary continence remained unchanged over time. Conclusion In summary, ALIF and lumbar TDR do not seem to negatively influence sexual and urinary function in females. In contrast, increased sexual desire was noted, likely secondary to post-surgical pain relief. KW - ALIF KW - dysfunction KW - FSFI KW - ICIQ KW - questionnaire KW - TDR KW - women Y1 - 2018 U6 - https://doi.org/10.1002/nau.23874 SN - 0733-2467 SN - 1520-6777 VL - 38 IS - 2 SP - 632 EP - 636 PB - Wiley CY - Hoboken ER - TY - GEN A1 - Wright, Michelle F. A1 - Wachs, Sebastian A1 - Harper, Bridgette D. T1 - The moderation of empathy in the longitudinal association between witnessing cyberbullying, depression, and anxiety T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - While the role of and consequences of being a bystander to face-to-face bullying has received some attention in the literature, to date, little is known about the effects of being a bystander to cyberbullying. It is also unknown how empathy might impact the negative consequences associated with being a bystander of cyberbullying. The present study focused on examining the longitudinal association between bystander of cyberbullying depression, and anxiety, and the moderating role of empathy in the relationship between bystander of cyberbullying and subsequent depression and anxiety. There were 1,090 adolescents (M-age = 12.19; 50% female) from the United States included at Time 1, and they completed questionnaires on empathy, cyberbullying roles (bystander, perpetrator, victim), depression, and anxiety. One year later, at Time 2, 1,067 adolescents (M-age = 13.76; 51% female) completed questionnaires on depression and anxiety. Results revealed a positive association between bystander of cyberbullying and depression and anxiety. Further, empathy moderated the positive relationship between bystander of cyberbullying and depression, but not for anxiety. Implications for intervention and prevention programs are discussed. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 689 KW - bystander KW - cyberbullying KW - empathy KW - depression KW - anxiety KW - longitudinal Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-470505 SN - 1866-8364 IS - 689 ER - TY - JOUR A1 - Wright, Michelle F. A1 - Wachs, Sebastian A1 - Harper, Bridgette D. T1 - The moderation of empathy in the longitudinal association between witnessing cyberbullying, depression, and anxiety JF - Journal of Psychosocial Research on Cyberspace N2 - While the role of and consequences of being a bystander to face-to-face bullying has received some attention in the literature, to date, little is known about the effects of being a bystander to cyberbullying. It is also unknown how empathy might impact the negative consequences associated with being a bystander of cyberbullying. The present study focused on examining the longitudinal association between bystander of cyberbullying depression, and anxiety, and the moderating role of empathy in the relationship between bystander of cyberbullying and subsequent depression and anxiety. There were 1,090 adolescents (M-age = 12.19; 50% female) from the United States included at Time 1, and they completed questionnaires on empathy, cyberbullying roles (bystander, perpetrator, victim), depression, and anxiety. One year later, at Time 2, 1,067 adolescents (M-age = 13.76; 51% female) completed questionnaires on depression and anxiety. Results revealed a positive association between bystander of cyberbullying and depression and anxiety. Further, empathy moderated the positive relationship between bystander of cyberbullying and depression, but not for anxiety. Implications for intervention and prevention programs are discussed. KW - Bystander KW - cyberbullying KW - empathy KW - depression KW - anxiety KW - longitudinal Y1 - 2018 U6 - https://doi.org/10.5817/CP2018-4-6 SN - 1802-7962 VL - 12 IS - 4 PB - Masrykova Univ. CY - Brno ER - TY - GEN A1 - Wright, Michelle F. A1 - Wachs, Sebastian T1 - Does parental mediation moderate the longitudinal association among bystanders and perpetrators and victims of cyberbullying? T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The purpose of the present study was to examine the moderation of parental mediation in the longitudinal association between being a bystander of cyberbullying and cyberbullying perpetration and cyberbullying victimization. Participants were 1067 7th and 8th graders between 12 and 15 years old (51% female) from six middle schools in predominantly middle-class neighborhoods in the Midwestern United States. Increases in being bystanders of cyberbullying was related positively to restrictive and instructive parental mediation. Restrictive parental mediation was related positively to Time 2 (T2) cyberbullying victimization, while instructive parental mediation was negatively related to T2 cyberbullying perpetration and victimization. Restrictive parental mediation was a moderator in the association between bystanders of cyberbullying and T2 cyberbullying victimization. Increases in restrictive parental mediation strengthened the positive relationship between these variables. In addition, instructive mediation moderated the association between bystanders of cyberbullying and T2 cyberbullying victimization such that increases in this form of parental mediation strategy weakened the association between bystanders of cyberbullying and T2 cyberbullying victimization. The current findings indicate a need for parents to be aware of how they can impact adolescents’ involvement in cyberbullying as bullies and victims. In addition, greater attention should be given to developing parental intervention programs that focus on the role of parents in helping to mitigate adolescents’ likelihood of cyberbullying involvement. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 679 KW - cyberbullying KW - bystander KW - bystanding KW - victimization KW - perpetration KW - bully KW - parental mediation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472303 SN - 1866-8364 IS - 679 ER - TY - JOUR A1 - Wright, Michelle F. A1 - Harper, Bridgette D. A1 - Wachs, Sebastian T1 - Differences in Adolescents’ Response Decision and Evaluation for Face-to-Face and Cyber Victimization JF - The Journal of Early Adolescence N2 - The current study was designed to assess early adolescents’ response evaluation and decision for hypothetical peer victimization vignettes. Participants were 336 (59% girls; X¯¯¯ age = 12.55) seventh and eighth graders from one school in the Midwestern United States. Adolescents read a hypothetical online or offline social situation and answered questions designed to access internal congruence, response evaluation, response efficacy, emotional outcome expectancy, and social outcome expectancy. Girls were more likely to believe that aggressive responses online and offline would lead to positive social and emotional outcome expectancies when compared with boys. Adolescents were more likely to believe that offline and online aggressive responses were legitimate responses to face-to-face victimization, feel that aggressive responses online or offline were easier to execute in response to face-to-face victimization, and that aggressive responses online or offline would lead to positive emotions and better social outcomes. KW - response decision KW - response evaluation KW - cyber aggression KW - cyberbullying KW - aggression KW - bullying Y1 - 2018 U6 - https://doi.org/10.1177/0272431618806052 SN - 0272-4316 SN - 1552-5449 VL - 39 IS - 8 SP - 1110 EP - 1128 PB - Sage Publ. CY - Thousand Oaks ER - TY - JOUR A1 - Wozniak, Natalia Joanna A1 - Sicard, Adrien T1 - Evolvability of flower geometry BT - Convergence in pollinator-driven morphological evolution of flowers JF - Seminars in cell & developmental biology N2 - Flowers represent a key innovation during plant evolution. Driven by reproductive optimization, evolution of flower morphology has been central in boosting species diversification. In most cases, this has happened through specialized interactions with animal pollinators and subsequent reduction of gene flow between specialized morphs. While radiation has led to an enormous variability in flower forms and sizes, recurrent evolutionary patterns can be observed. Here, we discuss the targets of selection involved in major trends of pollinator-driven flower evolution. We review recent findings on their adaptive values, developmental grounds and genetic bases, in an attempt to better understand the repeated nature of pollinator-driven flower evolution. This analysis highlights how structural innovation can provide flexibility in phenotypic evolution, adaptation and speciation. (C) 2017 Elsevier Ltd. All rights reserved. KW - Flower KW - Developmental evolution KW - Morphogenesis KW - Angiosperms KW - Co-evolution KW - Plant-pollinator interactions Y1 - 2018 U6 - https://doi.org/10.1016/j.semcdb.2017.09.028 SN - 1084-9521 VL - 79 SP - 3 EP - 15 PB - Elsevier CY - London ER - TY - JOUR A1 - Woutersen, Amber A1 - Jardine, Phillip E. A1 - Giovanni Bogota-Angel, Raul A1 - Zhang, Hong-Xiang A1 - Silvestro, Daniele A1 - Antonelli, Alexandre A1 - Gogna, Elena A1 - Erkens, Roy H. J. A1 - Gosling, William D. A1 - Dupont-Nivet, Guillaume A1 - Hoorn, Carina T1 - A novel approach to study the morphology and chemistry of pollen in a phylogenetic context, applied to the halophytic taxon Nitraria L.(Nitrariaceae) JF - PeerJ N2 - Nitraria is a halophytic taxon (i.e., adapted to saline environments) that belongs to the plant family Nitrariaceae and is distributed from the Mediterranean, across Asia into the south-eastern tip of Australia. This taxon is thought to have originated in Asia during the Paleogene (66-23 Ma), alongside the proto-Paratethys epicontinental sea. The evolutionary history of Nitraria might hold important clues on the links between climatic and biotic evolution but limited taxonomic documentation of this taxon has thus far hindered this line of research. Here we investigate if the pollen morphology and the chemical composition of the pollen wall are informative of the evolutionary history of Nitraria and could explain if origination along the proto-Paratethys and dispersal to the Tibetan Plateau was simultaneous or a secondary process. To answer these questions, we applied a novel approach consisting of a combination of Fourier Transform Infrared spectroscopy (FTIR), to determine the chemical composition of the pollen wall, and pollen morphological analyses using Light Microscopy (LM) and Scanning Electron Microscopy (SEM). We analysed our data using ordinations (principal components analysis and non-metric multidimensional scaling), and directly mapped it on the Nitrariaceae phylogeny to produce a phylomorphospace and a phylochemospace. Our LM, SEM and FTIR analyses show clear morphological and chemical differences between the sister groups Peganum and Nitraria. Differences in the morphological and chemical characteristics of highland species (Nitraria schoberi, N. sphaerocarpa, N. sibirica and N. tangutorum) and lowland species (Nitraria billardierei and N. retusa) are very subtle, with phylogenetic history appearing to be a more important control on Nitraria pollen than local environmental conditions. Our approach shows a compelling consistency between the chemical and morphological characteristics of the eight studied Nitrariaceae species, and these traits are in agreement with the phylogenetic tree. Taken together, this demonstrates how novel methods for studying fossil pollen can facilitate the evolutionary investigation of living and extinct taxa, and the environments they represent. KW - FTIR KW - LM KW - SEM KW - Paratethys KW - Tibet KW - Sporopollenin KW - Mediterranean KW - Steppe-desert KW - Australia KW - Palynology Y1 - 2018 U6 - https://doi.org/10.7717/peerj.5055 SN - 2167-8359 VL - 6 PB - PeerJ Inc. CY - London ER - TY - GEN A1 - Woodfield, Emma E. A1 - Horne, Richard B. A1 - Glauert, Sarah A. A1 - Menietti, John D. A1 - Shprits, Yuri Y. A1 - Kurth, William S. T1 - Formation of electron radiation belts at Saturn by Z-mode wave acceleration T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - At Saturn electrons are trapped in the planet's magnetic field and accelerated to relativistic energies to form the radiation belts, but how this dramatic increase in electron energy occurs is still unknown. Until now the mechanism of radial diffusion has been assumed but we show here that in-situ acceleration through wave particle interactions, which initial studies dismissed as ineffectual at Saturn, is in fact a vital part of the energetic particle dynamics there. We present evidence from numerical simulations based on Cassini spacecraft data that a particular plasma wave, known as Z-mode, accelerates electrons to MeV energies inside 4 R-S (1 R-S = 60,330 km) through a Doppler shifted cyclotron resonant interaction. Our results show that the Z-mode waves observed are not oblique as previously assumed and are much better accelerators than O-mode waves, resulting in an electron energy spectrum that closely approaches observed values without any transport effects included. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1032 KW - astrophysical plasmas KW - giant planets KW - magnetospheric physics KW - diffusion KW - pitch angle KW - plasma KW - radio KW - region Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468342 SN - 1866-8372 IS - 1032 ER - TY - JOUR A1 - Woodfield, Emma E. A1 - Horne, Richard B. A1 - Glauert, S. A. A1 - Menietti, J. D. A1 - Shprits, Yuri Y. A1 - Kurth, William S. T1 - Formation of electron radiation belts at Saturn by Z-mode wave acceleration JF - Nature Communications N2 - At Saturn electrons are trapped in the planet’s magnetic field and accelerated to relativistic energies to form the radiation belts, but how this dramatic increase in electron energy occurs is still unknown. Until now the mechanism of radial diffusion has been assumed but we show here that in-situ acceleration through wave particle interactions, which initial studies dismissed as ineffectual at Saturn, is in fact a vital part of the energetic particle dynamics there. We present evidence from numerical simulations based on Cassini spacecraft data that a particular plasma wave, known as Z-mode, accelerates electrons to MeV energies inside 4 RS (1 RS = 60,330 km) through a Doppler shifted cyclotron resonant interaction. Our results show that the Z-mode waves observed are not oblique as previously assumed and are much better accelerators than O-mode waves, resulting in an electron energy spectrum that closely approaches observed values without any transport effects included. Y1 - 2018 U6 - https://doi.org/10.1038/s41467-018-07549-4 SN - 2041-1723 VL - 9 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Wolter, Juliane A1 - Lantuit, Hugues A1 - Wetterich, Sebastian A1 - Rethemeyer, Janet A1 - Fritz, Michael T1 - Climatic, geomorphologic and hydrologic perturbations as drivers for mid- to late Holocene development of ice-wedge polygons in the western Canadian Arctic JF - Permafrost and Periglacial Processes N2 - Ice-wedge polygons are widespread periglacial features and influence landscape hydrology and carbon storage. The influence of climate and topography on polygon development is not entirely clear, however, giving high uncertainties to projections of permafrost development. We studied the mid- to late Holocene development of modern ice-wedge polygon sites to explore drivers of change and reasons for long-term stability. We analyzed organic carbon, total nitrogen, stable carbon isotopes, grain size composition and plant macrofossils in six cores from three polygons. We found that ail sites developed from aquatic to wetland conditions. In the mid-Holocene, shallow lakes and partly submerged ice-wedge polygons existed at the studied sites. An erosional hiatus of ca 5000 years followed, and ice-wedge polygons re-initiated within the last millennium. Ice-wedge melt and surface drying during the last century were linked to climatic warming. The influence of climate on ice-wedge polygon development was outweighed by geomorphology during most of the late Holocene. Recent warming, however, caused ice-wedge degradation at all sites. Our study showed that where waterlogged ground was maintained, low-centered polygons persisted for millennia. Ice-wedge melt and increased drainage through geomorphic disturbance, however, triggered conversion into high-centered polygons and may lead to self-enhancing degradation under continued warming. KW - carbon KW - lowland coasts KW - permafrost degradation KW - plant macrofossil analysis KW - tundra vegetation KW - western Canadian Arctic Y1 - 2018 U6 - https://doi.org/10.1002/ppp.1977 SN - 1045-6740 SN - 1099-1530 VL - 29 IS - 3 SP - 164 EP - 181 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Wolff, Christian Michael A1 - Frischmann, Peter D. A1 - Schulze, Marcus A1 - Bohn, Bernhard J. A1 - Wein, Robin A1 - Livadas, Panajotis A1 - Carlson, Michael T. A1 - Jäckel, Frank A1 - Feldmann, Jochen A1 - Würthner, Frank A1 - Stolarczyk, Jacek K. T1 - All-in-one visible-light-driven water splitting by combining nanoparticulate and molecular co-catalysts on CdS nanorods JF - Nature Energy N2 - Full water splitting into hydrogen and oxygen on semiconductor nanocrystals is a challenging task; overpotentials must be overcome for both half-reactions and different catalytic sites are needed to facilitate them. Additionally, efficient charge separation and prevention of back reactions are necessary. Here, we report simultaneous H-2 and O-2 evolution by CdS nanorods decorated with nanoparticulate reduction and molecular oxidation co-catalysts. The process proceeds entirely without sacrificial agents and relies on the nanorod morphology of CdS to spatially separate the reduction and oxidation sites. Hydrogen is generated on Pt nanoparticles grown at the nanorod tips, while Ru(tpy)(bpy)Cl-2-based oxidation catalysts are anchored through dithiocarbamate bonds onto the sides of the nanorod. O-2 generation from water was verified by O-18 isotope labelling experiments, and time-resolved spectroscopic results confirmed efficient charge separation and ultrafast electron and hole transfer to the reaction sites. The system demonstrates that combining nanoparticulate and molecular catalysts on anisotropic nanocrystals provides an effective pathway for visible-light-driven photocatalytic water splitting. Y1 - 2018 U6 - https://doi.org/10.1038/s41560-018-0229-6 SN - 2058-7546 VL - 3 IS - 10 SP - 862 EP - 869 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Wolf, Isabell Ann-Cathrin A1 - Gilles, Maria A1 - Peus, Verena A1 - Scharnholz, Barbara A1 - Seibert, Julia A1 - Jennen-Steinmetz, Christine A1 - Krumm, Bertram A1 - Rietschel, Marcella A1 - Deuschle, Michael A1 - Laucht, Manfred T1 - Impact of prenatal stress on mother-infant dyadic behavior during the still-face paradigm JF - Borderline Personality Disorder and Emotion Dysregulation : the official journal of the National Education Alliance for Borderline Personality Disorder (NEA.BPD) and Dachverband Dialektisch Behaviorale Therapie (DDBT) N2 - Background: Mother-infant interaction provides important training for the infant’s ability to cope with stress and the development of resilience. Prenatal stress (PS) and its impact on the offspring’s development have long been a focus of stress research, with studies highlighting both harmful and beneficial effects. The aim of the current study was to examine the possible influence of both psychological stress and hypothalamic-pituitary-adrenal (HPA) axis activity during pregnancy with mother-child dyadic behavior following stress exposure. Methods: The behavior of 164 mother-infant dyads during the still-face situation was filmed at six months postpartum and coded into three dyadic patterns: 1) both positive, 2) infant protesting-mother positive, and 3) infant protesting-mother negative. PS exposure was assessed prenatally according to psychological measures (i.e., psychopathological, perceived and psychosocial PS; n = 164) and HPA axis activity measures (maternal salivary cortisol, i.e., cortisol decline and area under the curve with respect to ground (AUCg); n = 134). Results: Mother-infant dyads in both the high- and low-stress groups showed decreasing positive and increasing negative dyadic behavior in the reunion episode, which is associated with the well-known “still-face” and “carry-over” effect. Furthermore, mother-infant dyads with higher psychosocial PS exhibited significantly more positive dyadic behavior than the low psychosocial PS group in the first play episode, but not in the reunion episode. Similarly, mother-infant dyads with high HPA axis activity (i.e. high AUCg) but steeper diurnal cortisol decline (i.e. cortisol decline) displayed significantly less negative behavior in the reunion episode than dyads with low HPA axis activity. No significant results were found for psychopathological stress and perceived stress. Conclusions: The results suggest a beneficial effect of higher psychosocial PS and higher prenatal maternal HPA axis activity in late gestation, which is in line with “stress inoculation” theories. KW - Prenatal stress KW - Face-to-face still-face paradigm KW - Resilience KW - Psychosocial stress KW - Cortisol Y1 - 2018 U6 - https://doi.org/10.1186/s40479-018-0078-8 SN - 2051-6673 VL - 5 PB - BioMed Central CY - London ER - TY - JOUR A1 - Wojcik, Robin A1 - Donhauser, Johanna A1 - Frey, Beat W. A1 - Holm, Stine A1 - Holland, Alexandra A1 - Anesio, Alexandre M. A1 - Pearce, David A. A1 - Malard, Lucie A1 - Wagner, Dirk A1 - Benning, Liane G. T1 - Linkages between geochemistry and microbiology in a proglacial terrain in the High Arctic JF - Annals of glaciology N2 - Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, delta C-13(org) and delta N-15 isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain. KW - biogeochemistry KW - glacial geomorphology KW - glacier chemistry KW - microbiology KW - processes and landforms of glacial erosion Y1 - 2018 U6 - https://doi.org/10.1017/aog.2019.1 SN - 0260-3055 SN - 1727-5644 VL - 59 IS - 77 SP - 95 EP - 110 PB - Cambridge Univ. Press CY - Cambridge ER - TY - JOUR A1 - Woith, Heiko A1 - Petersen, Gesa Maria A1 - Hainzl, Sebastian A1 - Dahm, Torsten T1 - Review: Can Animals Predict Earthquakes? JF - Bulletin of the Seismological Society of America N2 - In public perception, abnormal animal behavior is widely assumed to be a potential earthquake precursor, in strong contrast to the viewpoint in natural sciences. Proponents of earthquake prediction via animals claim that animals feel and react abnormally to small changes in environmental and physico-chemical parameters related to the earthquake preparation process. In seismology, however, observational evidence for changes of physical parameters before earthquakes is very weak. In this study, we reviewed 180 publications regarding abnormal animal behavior before earthquakes and analyze and discuss them with respect to (1) magnitude-distance relations, (2) foreshock activity, and (3) the quality and length of the published observations. More than 700 records of claimed animal precursors related to 160 earthquakes are reviewed with unusual behavior of more than 130 species. The precursor time ranges from months to seconds prior to the earthquakes, and the distances from a few to hundreds of kilometers. However, only 14 time series were published, whereas all other records are single observations. The time series are often short (the longest is 1 yr), or only small excerpts of the full data set are shown. The probability density of foreshocks and the occurrence of animal precursors are strikingly similar, suggesting that at least parts of the reported animal precursors are in fact related to foreshocks. Another major difficulty for a systematic and statistical analysis is the high diversity of data, which are often only anecdotal and retrospective. The study clearly demonstrates strong weaknesses or even deficits in many of the published reports on possible abnormal animal behavior. To improve the research on precursors, we suggest a scheme of yes and no questions to be assessed to ensure the quality of such claims. Y1 - 2018 U6 - https://doi.org/10.1785/0120170313 SN - 0037-1106 SN - 1943-3573 VL - 108 IS - 3A SP - 1031 EP - 1045 PB - Seismological Society of America CY - Albany ER - TY - THES A1 - Witt, Tanja Ivonne T1 - Camera Monitoring at volcanoes T1 - Kameramonitoring an Vulkanen BT - Identification and characterization of lava fountain activity and near-vent processes and their relevance for early warning systems BT - Identifikation und Charakterizierung der Aktivität von Lavafontänen und Near-Vent Prozesse und deren Relevanz für Frühwarnsysteme N2 - Basaltic fissure eruptions, such as on Hawai'i or on Iceland, are thought to be driven by the lateral propagation of feeder dikes and graben subsidence. Associated solid earth processes, such as deformation and structural development, are well studied by means of geophysical and geodetic technologies. The eruptions themselves, lava fountaining and venting dynamics, in turn, have been much less investigated due to hazardous access, local dimension, fast processes, and resulting poor data availability. This thesis provides a detailed quantitative understanding of the shape and dynamics of lava fountains and the morphological changes at their respective eruption sites. For this purpose, I apply image processing techniques, including drones and fixed installed cameras, to the sequence of frames of video records from two well-known fissure eruptions in Hawai'i and Iceland. This way I extract the dimensions of multiple lava fountains, visible in all frames. By putting these results together and considering the acquisition times of the frames I quantify the variations in height, width and eruption velocity of the lava fountains. Then I analyse these time-series in both time and frequency domains and investigate the similarities and correlations between adjacent lava fountains. Following this procedure, I am able to link the dynamics of the individual lava fountains to physical parameters of the magma transport in the feeder dyke of the fountains. The first case study in this thesis focuses on the March 2011 Pu'u'O'o eruption, Hawai'i, where a continuous pulsating behaviour at all eight lava fountains has been observed. The lava fountains, even those from different parts of the fissure that are closely connected, show a similar frequency content and eruption behaviour. The regular pattern in the heights of lava fountain suggests a controlling process within the magma feeder system like a hydraulic connection in the underlying dyke, affecting or even controlling the pulsating behaviour. The second case study addresses the 2014-2015 Holuhraun fissure eruption, Iceland. In this case, the feeder dyke is highlighted by the surface expressions of graben-like structures and fault systems. At the eruption site, the activity decreases from a continuous line of fire of ~60 vents to a limited number of lava fountains. This can be explained by preferred upwards magma movements through vertical structures of the pre-eruptive morphology. Seismic tremors during the eruption reveal vent opening at the surface and/or pressure changes in the feeder dyke. The evolving topography of the cinder cones during the eruption interacts with the lava fountain behaviour. Local variations in the lava fountain height and width are controlled by the conduit diameter, the depth of the lava pond and the shape of the crater. Modelling of the fountain heights shows that long-term eruption behaviour is controlled mainly by pressure changes in the feeder dyke. This research consists of six chapters with four papers, including two first author and two co-author papers. It establishes a new method to analyse lava fountain dynamics by video monitoring. The comparison with the seismicity, geomorphologic and structural expressions of fissure eruptions shows a complex relationship between focussed flow through dykes, the morphology of the cinder cones, and the lava fountain dynamics at the vents of a fissure eruption. N2 - Basaltische Spalteneruptionen, wie auf Hawaii oder Island, werden vermutlich durch die laterale Ausbreitung von Förderdikes und damit verbundener Grabenbildung verursacht. Prozesse der festen Erde sind mittels geophysikalischer und geodätischer Technologien gut erforscht. Die Ausbrüche selbst, d.h. die Lavafontä}nen und die Ventdynamik wiederum wurden aufgrund des gefährlichen Zugangs, der lokalen Dimension, der schnellen Prozesse und der daraus resultierenden schlechten Datenverfügbarkeit kaum untersucht. Diese Arbeit liefert ein detailliertes quantitatives Verständnis über Form und Dynamik von Lavafontänen und der morphologischen Veränderungen an ihren jeweiligen Eruptionsstellen. Mittels Bildverarbeitungstechniken, einschließlich Dronen und festen Kameras, wurden von mir die Videoframes von zwei bekannten Spaltausbrüchen auf Hawaii und Island ausgewertet. Auf diese Weise extrahiere ich die Dimensionen mehrerer Lavafontänen, die in allen Frames sichtbar sind. Durch die Zusammenstellung dieser Ergebnisse und unter Berücksichtigung der Erfassungszeiten quantifiziere ich die Schwankungen in Höhe, Breite und Eruptionsgeschwindigkeit. Dann analysiere ich diese Zeitreihen im Zeit- und Frequenzbereich und untersuche die Ähnlichkeiten und Zusammenhänge zwischen benachbarten Lavafontänen. Anschließend verknüpfte ich die Dynamik der einzelnen Lavafontänen mit den physikalischen Parametern des Magmatransports im Förderdike. Die erste Fallstudie dieser Arbeit konzentriert sich auf die Pu'u'O'o Ausbruch, Hawaii im März 2011, bei der ein kontinuierliches pulsierendes Verhalten an allen Lavafontänen beobachtet werden konnte. Lavafontänen verschiedener Teilsegmenten der Spalte sind eng miteinander verbunden, sie weisen Ähnlichkeiten im Frequenzgehalt und Ausbruchsverhalten auf. Das regelmäßige Muster in den Lavafontänenhöhen deutet auf eine hydraulische Verbindung im darunter liegenden Dike als steuernden Prozess innerhalb des Magma-Fördersystems hin. Die zweite Fallstudie befasst sich mit dem Holuhraun-Ausbruch 2014/2015. In diesem Fall wird der horizontale Förderdike durch grabenartige Strukturen und Bruchsysteme an der Oberfläche hervorgehoben. An der Ausbruchsstelle nimmt die Aktivität von einer kontinuierlichen Feuerlinie auf einzelne Lavafontänen ab. Dies lässt sich durch eine bevorzugte Aufwärtsbewegung des Magmas durch vertikale Strukturen der prä-eruptiven Morphologie erklären. Seismische Erschütterungen während des Ausbruchs zeigen Ventöffnungen an der Oberfläche und/oder Druckveränderungen im Förderdike. Die sich während des Ausbruchs entwickelnde Topographie der Schlackenkegel interagiert mit dem Verhalten der Lavafontänen. Lokale Schwankungen in Höhe und Breite der Lavafontäne werden jedoch durch den Schlotdurchmesser, die Tiefe des Lavaponds und die Form des Kraters gesteuert. Die Modellierung der Fontänenhöhe zeigt, dass das langfristige Ausbruchsverhalten vor allem durch Druckänderungen im Förderdike gesteuert wird. Diese Forschungsarbeit besteht aus sechs Kapiteln mit je zwei Papern als Erst- bzw. Co-Autor. Es etabliert eine neue Methode zur Analyse der Dynamik von Lavafontänen durch Videoüberwachung. Der Vergleich mit der Seismizität, den geomorphologischen und strukturellen Ausprägungen von Spalteneruptionen zeigt einen komplexen Zusammenhang zwischen der Dikeströmung, der Vulkanmorphologie und der Dynamik der Lavafontänen an einer Spalteneruption. KW - volcanology KW - Spalteneruption KW - fissure eruption KW - Vulkanologie KW - lava fountains KW - video analysis KW - basaltic volcanoes KW - Lavafontänen KW - Videoanalyse KW - Basalt-Vulkane Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-421073 ER -