TY - CHAP A1 - Rehak, Katrin A1 - Strecker, Manfred A1 - Echtler, Helmut Peter T1 - DEM supported tectonic geomorphology : the Coastal Cordillera of the South-Central Chilean active margin ; [Poster] N2 - Fluvial systems are one of the major features shaping a landscape. They adjust to the prevailing tectonic and climatic setting and therefore are very sensitive markers of changes in these systems. If their response to tectonic and climatic forcing is quantified and if the climatic signal is excluded, it is possible to derive a local deformation history. Here, we investigate fluvial terraces and erosional surfaces in the southern Chilean forearc to assess a long-term geomorphic and hence tectonic evolution. Remote sensing and field studies of the Nahuelbuta Range show that the long-term deformation of the Chilean forearc is manifested by breaks in topography, sequences of differentially uplifted marine, alluvial and strath terraces as well as tectonically modified river courses and drainage basins. We used SRTM-90-data as basic elevation information for extracting and delineating drainage networks. We calculated hypsometric curves as an indicator for basin uplift, stream-length gradient indices to identify stream segments with anomalous slopes, and longitudinal river profiles as well as DS-plots to identify knickpoints and other anomalies. In addition, we investigated topography with elevation-slope graphs, profiles, and DEMs to reveal erosional surfaces. During the first field trip we already measured palaeoflow directions, performed pebble counting and sampled the fluvial terraces in order to apply cosmogenic nuclide dating (10Be, 26Al) as well as provenance analyses. Our preliminary analysis of the Coastal Cordillera indicates a clear segmentation between the northern and southern parts of the Nahuelbuta Range. The Lanalhue Fault, a NW-SE striking fault zone oblique to the plate boundary, defines the segment boundary. Furthermore, we find a complex drainage re-organisation including a drainage reversal and wind gap on the divide between the Tirúa and Pellahuén basins east of the town Tirúa. The coastal basins lost most of their Andean sediment supply areas that existed in Tertiary and in part during early Pleistocene time. Between the Bío-Bío and Imperial rivers no Andean river is recently capable to traverse the Coastal Cordillera, suggesting ongoing Quaternary uplift of the entire range. From the spatial distribution of geomorphic surfaces in this region two uplift signals may be derived: (1) a long-term differential uplift process, active since the Miocene and possibly caused by underplating of subducted trench sediments, (2) a younger, local uplift affecting only the northern part of the Nahuelbuta Range that may be caused by the interaction of the forearc with the subduction of the Mocha Fracture Zone at the latitude of the Arauco peninsula. Our approach thus provides results in our attempt to decipher the characteristics of forearc development of active convergent margins using long-term geomorphic indicators. Furthermore, it is expected that our ongoing assessment will constrain repeatedly active zones of deformation.
Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7224 ER - TY - GEN A1 - Reich, Oliver A1 - Löhmannsröben, Hans-Gerd A1 - Schael, Frank T1 - Optical sensing with photon density waves: investigation of model media N2 - Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 026 Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13147 ER - TY - CHAP A1 - Reimer, A. T1 - Clumping effects on non-thermal particle spectra in massive star systems N2 - Observational evidence exists that winds of massive stars are clumped. Many massive star systems are known as non-thermal particle production sites, as indicated by their synchrotron emission in the radio band. As a consequence they are also considered as candidate sites for non-thermal high-energy photon production up to gamma-ray energies. The present work considers the effects of wind clumpiness expected on the emitting relativistic particle spectrum in colliding wind systems, built up from the pool of thermal wind particles through diffusive particle acceleration, and taking into account inverse Compton and synchrotron losses. In comparison to a homogeneous wind, a clumpy wind causes flux variations of the emitting particle spectrum when the clump enters the wind collision region. It is found that the spectral features associated with this variability moves temporally from low to high energy bands with the time shift between any two spectral bands being dependent on clump size, filling factor, and the energy-dependence of particle energy gains and losses. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18246 ER - TY - CHAP A1 - Reimer, O. A1 - Aharonian, Felix A. A1 - Hinton, J. A1 - Hofmann, W. A1 - Hoppe, S. A1 - Raue, M. A1 - Reimer, A. T1 - VHE gamma-rays from Westerlund 2 and implications for the inferred energetics N2 - The H.E.S.S. collaboration recently reported the discovery of VHE γ-ray emission coincident with the young stellar cluster Westerlund 2. This system is known to host a population of hot, massive stars, and, most particularly, the WR binary WR 20a. Particle acceleration to TeV energies in Westerlund 2 can be accomplished in several alternative scenarios, therefore we only discuss energetic constraints based on the total available kinetic energy in the system, the actual mass loss rates of respective cluster members, and implied gamma-ray production from processes such as inverse Compton scattering or neutral pion decay. From the inferred gammaray luminosity of the order of 1035erg/s, implications for the efficiency of converting available kinetic energy into non-thermal radiation associated with stellar winds in the Westerlund 2 cluster are discussed under consideration of either the presence or absence of wind clumping. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18172 ER - TY - CHAP A1 - Reyes-Iturbide, J. A1 - Velázquez, P. A1 - Rosado, M. T1 - 3D numerical model for an asymmetrical superbubble N2 - Massive stars usually form groups such as OB associations. Their fast stellar winds sweep up collectively the surrounding insterstellar medium (ISM) to generate superbubbles. Observations suggest that superbubble evolution on the surrounding ISM can be very irregular. Numerical simulations considering these conditions could help to understand the evolution of these superbubbles and to clarify the dynamics of these objects as well as the difference between observed X-ray luminosities and the predicted ones by the standard model (Weaver et al. 1977). Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17724 ER - TY - JOUR A1 - Richter, Eric A1 - Kunter, Mareike A1 - Marx, Alexandra A1 - Richter, Dirk T1 - Who participates in content-focused teacher professional development? BT - Evidence from a large scale study JF - Frontiers in education N2 - This study investigates the relationship between teacher quality and teachers’ engagement in professional development (PD) activities using data on 229 German secondary school mathematics teachers. We assessed different aspects of teacher quality (e.g. professional knowledge, instructional quality) using a variety of measures, including standardised tests of teachers’ content knowledge, to determine what characteristics are associated with high participation in PD. The results show that teachers with higher scores for teacher quality variables take part in more content-focused PD than teachers with lower scores for these variables. This suggests that teacher learning may be subject to a Matthew effect, whereby more proficient teachers benefit more from PD than less proficient teachers. KW - teacher learning KW - professional development KW - content knowledge KW - teacher quality KW - in-service training KW - Matthew effect KW - continuing education activities Y1 - 2021 U6 - https://doi.org/10.3389/feduc.2021.722169 SN - 2504-284X IS - 6 SP - 1 EP - 10 PB - Frontiers Media CY - Lausanne, Schweiz ER - TY - THES A1 - Richter, Maximilian Jacob Enzo Amandus T1 - Continental rift dynamics across the scales T1 - Dynamiken kontinentaler Grabenbrüche über die Skalen BT - numerical modelling of localisation processes BT - numerische Modellierung von Lokalisations-Prozessen N2 - Localisation of deformation is a ubiquitous feature in continental rift dynamics and observed across drastically different time and length scales. This thesis comprises one experimental and two numerical modelling studies investigating strain localisation in (1) a ductile shear zone induced by a material heterogeneity and (2) in an active continental rift setting. The studies are related by the fact that the weakening mechanisms on the crystallographic and grain size scale enable bulk rock weakening, which fundamentally enables the formation of shear zones, continental rifts and hence plate tectonics. Aiming to investigate the controlling mechanisms on initiation and evolution of a shear zone, the torsion experiments of the experimental study were conducted in a Patterson type apparatus with strong Carrara marble cylinders with a weak, planar Solnhofen limestone inclusion. Using state-of-the-art numerical modelling software, the torsion experiments were simulated to answer questions regarding localisation procedure like stress distribution or the impact of rheological weakening. 2D numerical models were also employed to integrate geophysical and geological data to explain characteristic tectonic evolution of the Southern and Central Kenya Rift. Key elements of the numerical tools are a randomized initial strain distribution and the usage of strain softening. During the torsion experiments, deformation begins to localise at the limestone inclusion tips in a process zone, which propagates into the marble matrix with increasing deformation until a ductile shear zone is established. Minor indicators for coexisting brittle deformation are found close to the inclusion tip and presumed to slightly facilitate strain localisation besides the dominant ductile deformation processes. The 2D numerical model of the torsion experiment successfully predicts local stress concentration and strain rate amplification ahead of the inclusion in first order agreement with the experimental results. A simple linear parametrization of strain weaking enables high accuracy reproduction of phenomenological aspects of the observed weakening. The torsion experiments suggest that loading conditions do not affect strain localisation during high temperature deformation of multiphase material with high viscosity contrasts. A numerical simulation can provide a way of analysing the process zone evolution virtually and extend the examinable frame. Furthermore, the nested structure and anastomosing shape of an ultramylonite band was mimicked with an additional second softening step. Rheological weakening is necessary to establish a shear zone in a strong matrix around a weak inclusion and for ultramylonite formation. Such strain weakening laws are also incorporated into the numerical models of the Southern and Central Kenya Rift that capture the characteristic tectonic evolution. A three-stage early rift evolution is suggested that starts with (1) the accommodation of strain by a single border fault and flexure of the hanging-wall crust, after which (2) faulting in the hanging-wall and the basin centre increases before (3) the early-stage asymmetry is lost and basinward localisation of deformation occurs. Along-strike variability of rifts can be produced by modifying the initial random noise distribution. In summary, the three studies address selected aspects of the broad range of mechanisms and processes that fundamentally enable the deformation of rock and govern the localisation patterns across the scales. In addition to the aforementioned results, the first and second manuscripts combined, demonstrate a procedure to find new or improve on existing numerical formulations for specific rheologies and their dynamic weakening. These formulations are essential in addressing rock deformation from the grain to the global scale. As within the third study of this thesis, where geodynamic controls on the evolution of a rift were examined and acquired by the integration of geological and geophysical data into a numerical model. N2 - Die Lokalisierung von Deformation ist ein allgegenwärtiges Merkmal in der Dynamik von Grabenbrüchen bzw. Riftzonen und wird über verschiedene Zeit- und Längenskalen beobachtet. Diese Arbeit umfasst eine experimentelle und zwei numerische Studien zur Untersuchung der Lokalisierung von Deformation in (1) einer durch eine Materialheterogenität induzierten duktilen Scherzone und (2) in einem aktiven Kontinentalgraben. Die Studien verbindet, dass die Schwächungsmechanismen auf der kristallographischen Skala und der Korngrößenskala eine Enthärtung eines Gesteinkörpers ermöglicht, was im Wesentlichen die Bildung von Scherzonen, Grabenbrüchen und damit Plattentektonik ermöglicht. Um die Kontrollmechanismen für die Initiierung und Entwicklung einer Scherzone zu untersuchen, wurden die Torsionsexperimente der experimentellen Studie in einem Patterson-Gerät an starken Carrara-Marmorzylinder mit einer schwachen, planaren Solnhofen-Kalksteineinschluss durchgeführt. Mit modernster numerischer Modellierungssoftware wurden die Torsionsexperimente simuliert, um weitere Fragen zum Lokalisierungsablauf wie die Verteilung der Spannung oder den Einfluss rheologischer Schwächung zu beantworten. Numerische 2D-Modelle wurden auch verwendet, um geophysikalische und geologische Daten zu kombinieren, um die charakteristische tektonische Entwicklung des südlichen und zentralen Kenia-Rifts zu erklären. Schlüsselelemente der verwendeten numerischen Werkzeuge sind eine randomisierte Anfangsverteilung des Strain und der Einsatz von Strain basierter Enthärtung. Während der Torsionsversuche lokalisiert die Deformation zunächst an den Kalksteineinschlussspitzen in einer Prozesszone, die sich mit zunehmender Deformation in die Marmormatrix ausbreitet bis sich eine duktile Scherzone einstellt. Neben den dominierenden duktilen Verformungsprozessen werden geringfügige Indikatoren für eine koexistierende spröde Verformung nahe der Einschlussspitzen gefunden und es wird angenommen, dass diese die Lokalisierung der Deformation geringfügig erleichtern. In erster Ordnung sagt das numerische 2D-Modell des Torsionsexperiments erfolgreich lokale Spannungskonzentration und Strainratenverstärkung vor der Inklusion in Übereinstimmung mit den experimentellen Ergebnissen vorher. Eine einfache lineare Parametrisierung der Enthärtung durch Strain ermöglicht eine genaue Reproduktion phänomenologischer Aspekte der beobachteten Schwächung. Die Torsionsexperimente legen nahe, dass die Randbedingungen die Lokalisierung des Strain während der Hochtemperaturverformung von Mehrphasenmaterial mit hohen Viskositätskontrasten nicht beeinflussen. Die numerische Simulation ermöglicht es, die Entwicklung der Prozesszone virtuell zu analysieren und den Untersuchungsrahmen zu erweitern. Darüber hinaus wurde die verschachtelte Struktur und anastomosierende Form eines Ultramylonitbandes mit einem zusätzlichen zweiten Enthärtungsschritt nachgeahmt. Die rheologische Schwächung ist notwendig, um eine Scherzone in einer starken Matrix um einen schwachen Einschluss herum und für die Ultramylonitbildung zu etablieren. Solche Schwächungsgesetze, die auf Strain basieren, fließen auch in die numerischen Modelle des südlichen und zentralen Kenia-Rifts ein, die die charakteristische tektonische Entwicklung erfassen. Es wird eine dreistufige frühe Riftentwicklung vorgeschlagen, die mit (1) der Anpassung von Spannungen durch eine einzelne Grenzstörung und Biegung der hangenden Kruste beginnt, wonach (2) die Verwerfung im Hangenden und im Beckenzentrum zunimmt, bevor (3) die Asymmetrie des Frühstadiums verloren geht und es zu einer beckenseitigen Deformationslokalisierung kommt. Die Variabilität von Rissen entlang des Rifts kann durch Modifizieren der anfänglichen zufälligen Rauschverteilung erzeugt werden. Zusammenfassend befassen sich die drei Studien mit ausgewählten Aspekten der breiten Palette von Mechanismen und Prozessen, die die Deformation von Gestein grundlegend ermöglichen und die Lokalisierungsmuster über die Skalen bestimmen. Zusätzlich zu den oben genannten Ergebnissen demonstrieren das erste und zweite Manuskript in Kombination ein Verfahren, um neue oder bestehende numerische Formulierungen für spezifische Rheologien und deren dynamische Schwächung zu finden oder zu verbessern. Diese Formulierungen sind essenziell, um Gesteinsverformung von der Korngrößen bis zur globalen Skala zu untersuchen. Wie in der dritten Studie dieser Dissertation, in der geodynamische Kontrollen auf die Entwicklung eines Grabenbruchs durch die Integration geologischer und geophysikalischer Daten in ein numerisches Modell untersucht und erfasst wurden. KW - Strain Localisation KW - Continental Rifts KW - Torsion Experiments KW - Geodynamic Modelling KW - 2D Numerical Modelling KW - Lokalisierung von Deformation KW - Grabenbrüche KW - Geodynamische Modellierung KW - Torsionsexperimente KW - Numerische 2D Modellierung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-550606 ER - TY - THES A1 - Rinne, Theresa Charlotte T1 - The effects of nutrients on bone stem cell function and regeneration N2 - Aging is associated with bone loss, which can lead to osteoporosis and high fracture risk. This coincides with the enhanced formation of bone marrow adipose tissue (BMAT), suggesting a negative effect of bone marrow adipocytes on skeletal health. Increased BMAT formation is also observed in pathologies such as obesity, type 2 diabetes and osteoporosis. However, a subset of bone marrow adipocytes forming the constitutive BMAT (cBMAT), arise early in life in the distal skeleton, contain high levels of unsaturated fatty acids and are thought to provide a physiological function. Regulated BMAT (rBMAT) forms during aging and obesity in proximal regions of the bone and contain a large proportion of saturated fatty acids. Paradoxically, BMAT accumulation is also enhanced during caloric restriction (CR), a life-span extending dietary intervention. This indicates, that different types of BMAT can form in response to opposing nutritional stimuli with potentially different functions. To this end, two types of nutritional interventions, CR and high fat diet (HFD), that are both described to induce BMAT accumulation were carried out. CR markedly increased BMAT formation in the proximal tibia and led to a higher proportion of unsaturated fatty acids, making it similar to the physiological cBMAT. Additionally, proximal and diaphyseal tibia regions displayed higher adiponectin expression. In aged mice, CR was associated with an improved trabecular bone structure. Taken together, these findings demonstrate, that the type of BMAT that forms during CR might provide beneficial effects for local bone stem/progenitor cells and metabolic health. The HFD intervention performed in this thesis showed no effect on BMAT accumulation and bone microstructure. RNA Seq analysis revealed alterations in the composition of the collagen-containing extracellular matrix (ECM). In order to investigate the effects of glucose homeostasis on osteogenesis, differentiation capacity of immortalized multipotent mesenchymal stromal cells (MSCs) and osteochondrogenic progenitor cells (OPCs) was analyzed. Insulin improved differentiation in both cell types, however, combination of with a high glucose concentration led to an impaired mineralization of the ECM. In the MSCs, this was accompanied by the formation of adipocytes, indicating negative effects of the adipocytes formed during hyperglycemic conditions on mineralization processes. However, the altered mineralization pattern and structure of the ECM was also observed in OPCs, which did not form any adipocytes, suggesting further negative effects of a hyperglycemic environment on osteogenic differentiation. In summary, the work provided in this thesis demonstrated that differentiation commitment of bone-resident stem cells can be altered through nutrient availability, specifically glucose. Surprisingly, both high nutrient supply, e.g. the hyperglycemic cell culture conditions, and low nutrient supply, e.g. CR, can induce adipogenic differentiation. However, while CR-induced adipocyte formation was associated with improved trabecular bone structure, adipocyte formation in a hyperglycemic cell-culture environment hampered mineralization. This thesis provides further evidence for the existence of different types of BMAT with specific functions. Y1 - 2024 ER - TY - JOUR A1 - Risch, Lucie A1 - Stoll, Josefine A1 - Schomöller, Anne A1 - Engel, Tilman A1 - Mayer, Frank A1 - Cassel, Michael T1 - Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons JF - Frontiers in physiology N2 - Objective: This study investigated intraindividual differences of intratendinous blood flow (IBF) in response to running exercise in participants with Achilles tendinopathy. Design: This is a cross-sectional study. Setting: The study was conducted at the University Outpatient Clinic. Participants: Sonographic detectable intratendinous blood flow was examined in symptomatic and contralateral asymptomatic Achilles tendons of 19 participants (42 ± 13 years, 178 ± 10 cm, 76 ± 12 kg, VISA-A 75 ± 16) with clinically diagnosed unilateral Achilles tendinopathy and sonographic evident tendinosis. Intervention: IBF was assessed using Doppler ultrasound “Advanced Dynamic Flow” before (Upre) and 5, 30, 60, and 120 min (U5–U120) after a standardized submaximal constant load run. Main Outcome Measure: IBF was quantified by counting the number (n) of vessels in each tendon. Results: At Upre, IBF was higher in symptomatic compared with asymptomatic tendons [mean 6.3 (95% CI: 2.8–9.9) and 1.7 (0.4–2.9), p < 0.01]. Overall, 63% of symptomatic and 47% of asymptomatic Achilles tendons responded to exercise, whereas 16 and 11% showed persisting IBF and 21 and 42% remained avascular throughout the investigation. At U5, IBF increased in both symptomatic and asymptomatic tendons [difference to baseline: 2.4 (0.3–4.5) and 0.9 (0.5–1.4), p = 0.05]. At U30 to U120, IBF was still increased in symptomatic but not in asymptomatic tendons [mean difference to baseline: 1.9 (0.8–2.9) and 0.1 (-0.9 to 1.2), p < 0.01]. Conclusion: Irrespective of pathology, 47–63% of Achilles tendons responded to exercise with an immediate acute physiological IBF increase by an average of one to two vessels (“responders”). A higher amount of baseline IBF (approximately five vessels) and a prolonged exercise-induced IBF response found in symptomatic ATs indicate a pain-associated altered intratendinous “neovascularization.” KW - achilles tendinopathy KW - tendinosis KW - neovascularization KW - ultrasound KW - advanced dynamic flow KW - sonography Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.617497 SN - 1664-042X VL - 12 SP - 1 EP - 8 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - THES A1 - Robalo, João Ramiro Alavedra Mendes T1 - Investigating the role of fluorinated amino acids on protein structure and function using simulation Y1 - 2018 ER - TY - THES A1 - Robinson, Alexander T1 - Modeling the Greenland Ice Sheet response to climate change in the past and future T1 - Modellierung der Reaktion des Grönländischen Inlandeises auf den vergangenen und zukünftigen Klimawandel N2 - The Greenland Ice Sheet (GIS) contains enough water volume to raise global sea level by over 7 meters. It is a relic of past glacial climates that could be strongly affected by a warming world. Several studies have been performed to investigate the sensitivity of the ice sheet to changes in climate, but large uncertainties in its long-term response still exist. In this thesis, a new approach has been developed and applied to modeling the GIS response to climate change. The advantages compared to previous approaches are (i) that it can be applied over a wide range of climatic scenarios (both in the deep past and the future), (ii) that it includes the relevant feedback processes between the climate and the ice sheet and (iii) that it is highly computationally efficient, allowing simulations over very long timescales. The new regional energy-moisture balance model (REMBO) has been developed to model the climate and surface mass balance over Greenland and it represents an improvement compared to conventional approaches in modeling present-day conditions. Furthermore, the evolution of the GIS has been simulated over the last glacial cycle using an ensemble of model versions. The model performance has been validated against field observations of the present-day climate and surface mass balance, as well as paleo information from ice cores. The GIS contribution to sea level rise during the last interglacial is estimated to be between 0.5-4.1 m, consistent with previous estimates. The ensemble of model versions has been constrained to those that are consistent with the data, and a range of valid parameter values has been defined, allowing quantification of the uncertainty and sensitivity of the modeling approach. Using the constrained model ensemble, the sensitivity of the GIS to long-term climate change was investigated. It was found that the GIS exhibits hysteresis behavior (i.e., it is multi-stable under certain conditions), and that a temperature threshold exists above which the ice sheet transitions to an essentially ice-free state. The threshold in the global temperature is estimated to be in the range of 1.3-2.3°C above preindustrial conditions, significantly lower than previously believed. The timescale of total melt scales non-linearly with the overshoot above the temperature threshold, such that a 2°C anomaly causes the ice sheet to melt in ca. 50,000 years, but an anomaly of 6°C will melt the ice sheet in less than 4,000 years. The meltback of the ice sheet was found to become irreversible after a fraction of the ice sheet is already lost – but this level of irreversibility also depends on the temperature anomaly. N2 - Das grönländische Inlandeis (GIS) besteht aus einem Wasservolumen das ausreicht, um den globalen Meeresspiegel um 7 Meter ansteigen zu lassen. Es ist ein Relikt der vergangenen Eiszeit, das in einer zunehmend wärmer werdenden Welt stark in Mitleidenschaft gezogen werden könnte. In der vorliegenden Dissertation ist ein neues Verfahren zur Modellierung des Antwortverhaltens des Inlandeises auf Klimaänderungen entwickelt und angewendet worden. Die Vorteile des neuen Verfahrens im Vergleich zu den bisherigen Verfahren sind, (i) dass es über einen groen Bereich von Klimaszenarien (sowohl für die ferne Vergangenheit als auch für die Zukunft) anwendbar ist, (ii) dass es die wesentlichen Rückkopplungsprozesse zwischen Klima und Inlandeis enthält und (iii) dass es wegen seiner guten Rechenzeiteffizienz Simulationen über sehr lange Zeitskalen erlaubt. Das neue Modell (REMBO) ist für die Modellierung des Klimas und der Massenbilanz an der grönländischen Oberfläche entwickelt worden und stellt ein verbessertes Verfahren im Vergleich zu den bisherigen dar. Die Entwicklung von GIS über den letzten glazialen Zyklus ist mittels eines Ensembles von verschiedenen Modellversionen simuliert worden. Anschließend ist die Tauglichkeit der Modellversionen durch Vergleich mit Beobachtungsdaten des gegenwärtigen Klimas und der Oberflächenmassenbilanz, sowie mit paleoklimatischen Rekonstruktionen von Eisbohrkernen verifiziert worden. Der Anteil von GIS am Meeresspiegelanstieg während des letzten Interglazials ist im Bereich von 0.5 bis 4.1 m berechnet worden, was konsistent mit bisherigen Schätzungen ist. Von den Ensemblesimulationen sind diejenigen ausgewählt worden, deren Ergebnisse gut mit den Daten übereinstimmen. Durch die Auswahl von geeigneten Modellversionen sind gleichzeitig die Unsicherheiten der Parameterwerte begrenzt worden, so dass sich nun mit dem neuen Verfahren die Sensitivität von GIS auf Klimaänderungen bestimmen lässt. Mit den ausgewählten Modellversionen ist die Sensitivität von GIS auf langfristige Klimaänderungen untersucht worden. Es zeigt sich, dass das GIS ein Hystereseverhalten besitzt (d.h., eine Multistabilität für gewisse Klimazustände) und dass ein Temperaturschwellwert existiert. Bei Überschreiten des Schwellwertes bleibt das GIS nicht erhalten und wird langsam eisfrei werden. Der Temperaturschwellwert der globalen Mitteltemperatur relativ zur vorindustriellen Mitteltemperatur ist im Bereich 1.3-2.3°C ermittelt worden und liegt damit deutlich niedriger als bisher angenommen. Die Zeitdauer bis zum völligen Abschmelzen zeigt ein nichtlineares Verhalten hinsichtlich einer Erwärmung über den ermittelten Schwellwert. Eine Erwärmung von 2°C relativ zur vorindustriellen Zeit führt zu einem Abschmelzen nach 50.000 Jahren, aber eine Erwärmung um 6°C lässt das Inlandeis bereits nach 4.000 Jahren abschmelzen. Ein weiteres Ergebnis ist, dass der Abschmelzvorgang irreversibel werden kann, nachdem ein gewisser Anteil des Inlandeises abgeschmolzen ist – jedoch ist die Irreversibilität eines Abschmelzvorganges auch von der Temperaturanomalie abhängig. KW - Grönland KW - Inlandeis KW - Klimawandel KW - Stabilität KW - Hysterese KW - Greenland KW - ice sheet KW - climate change KW - stability KW - hysteresis Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-50430 ER - TY - THES A1 - Rodriguez Piceda, Constanza T1 - Thermomechanical state of the southern Central Andes T1 - Thermomechanischer Zustand der südlichen Zentral Anden BT - implications for active deformation patterns in the transition from flat to steep subduction BT - Implikationen für aktive Deformationsmuster beim Übergang von flacher zu steiler Subduktion N2 - The Andes are a ~7000 km long N-S trending mountain range developed along the South American western continental margin. Driven by the subduction of the oceanic Nazca plate beneath the continental South American plate, the formation of the northern and central parts of the orogen is a type case for a non-collisional orogeny. In the southern Central Andes (SCA, 29°S-39°S), the oceanic plate changes the subduction angle between 33°S and 35°S from almost horizontal (< 5° dip) in the north to a steeper angle (~30° dip) in the south. This sector of the Andes also displays remarkable along- and across- strike variations of the tectonic deformation patterns. These include a systematic decrease of topographic elevation, of crustal shortening and foreland and orogenic width, as well as an alternation of the foreland deformation style between thick-skinned and thin-skinned recorded along- and across the strike of the subduction zone. Moreover, the SCA are a very seismically active region. The continental plate is characterized by a relatively shallow seismicity (< 30 km depth) which is mainly focussed at the transition from the orogen to the lowland areas of the foreland and the forearc; in contrast, deeper seismicity occurs below the interiors of the northern foreland. Additionally, frequent seismicity is also recorded in the shallow parts of the oceanic plate and in a sector of the flat slab segment between 31°S and 33°S. The observed spatial heterogeneity in tectonic and seismic deformation in the SCA has been attributed to multiple causes, including variations in sediment thickness, the presence of inherited structures and changes in the subduction angle of the oceanic slab. However, there is no study that inquired the relationship between the long-term rheological configuration of the SCA and the spatial deformation patterns. Moreover, the effects of the density and thickness configuration of the continental plate and of variations in the slab dip angle in the rheological state of the lithosphere have been not thoroughly investigated yet. Since rheology depends on composition, pressure and temperature, a detailed characterization of the compositional, structural and thermal fields of the lithosphere is needed. Therefore, by using multiple geophysical approaches and data sources, I constructed the following 3D models of the SCA lithosphere: (i) a seismically-constrained structural and density model that was tested against the gravity field; (ii) a thermal model integrating the conversion of mantle shear-wave velocities to temperature with steady-state conductive calculations in the uppermost lithosphere (< 50 km depth), validated by temperature and heat-flow measurements; and (iii) a rheological model of the long-term lithospheric strength using as input the previously-generated models. The results of this dissertation indicate that the present-day thermal and rheological fields of the SCA are controlled by different mechanisms at different depths. At shallow depths (< 50 km), the thermomechanical field is modulated by the heterogeneous composition of the continental lithosphere. The overprint of the oceanic slab is detectable where the oceanic plate is shallow (< 85 km depth) and the radiogenic crust is thin, resulting in overall lower temperatures and higher strength compared to regions where the slab is steep and the radiogenic crust is thick. At depths > 50 km, largest temperatures variations occur where the descending slab is detected, which implies that the deep thermal field is mainly affected by the slab dip geometry. The outcomes of this thesis suggests that long-term thermomechanical state of the lithosphere influences the spatial distribution of seismic deformation. Most of the seismicity within the continental plate occurs above the modelled transition from brittle to ductile conditions. Additionally, there is a spatial correlation between the location of these events and the transition from the mechanically strong domains of the forearc and foreland to the weak domain of the orogen. In contrast, seismicity within the oceanic plate is also detected where long-term ductile conditions are expected. I therefore analysed the possible influence of additional mechanisms triggering these earthquakes, including the compaction of sediments in the subduction interface and dehydration reactions in the slab. To that aim, I carried out a qualitative analysis of the state of hydration in the mantle using the ratio between compressional- and shear-wave velocity (vp/vs ratio) from a previous seismic tomography. The results from this analysis indicate that the majority of the seismicity spatially correlates with hydrated areas of the slab and overlying continental mantle, with the exception of the cluster within the flat slab segment. In this region, earthquakes are likely triggered by flexural processes where the slab changes from a flat to a steep subduction angle. First-order variations in the observed tectonic patterns also seem to be influenced by the thermomechanical configuration of the lithosphere. The mechanically strong domains of the forearc and foreland, due to their resistance to deformation, display smaller amounts of shortening than the relatively weak orogenic domain. In addition, the structural and thermomechanical characteristics modelled in this dissertation confirm previous analyses from geodynamic models pointing to the control of the observed heterogeneities in the orogen and foreland deformation style. These characteristics include the lithospheric and crustal thickness, the presence of weak sediments and the variations in gravitational potential energy. Specific conditions occur in the cold and strong northern foreland, which is characterized by active seismicity and thick-skinned structures, although the modelled crustal strength exceeds the typical values of externally-applied tectonic stresses. The additional mechanisms that could explain the strain localization in a region that should resist deformation are: (i) increased tectonic forces coming from the steepening of the slab and (ii) enhanced weakening along inherited structures from pre-Andean deformation events. Finally, the thermomechanical conditions of this sector of the foreland could be a key factor influencing the preservation of the flat subduction angle at these latitudes of the SCA. N2 - Die Anden sind eine ~7000 km lange N-S-verlaufende Hochgebirgskette, die entlang des westlichen südamerikanischen Kontinentalrandes entstanden ist. Aufgrund der Subduktion der ozeanischen Nazca-Platte unter die kontinentale südamerikanische Platte ist die Bildung des nördlichen und zentralen Teils des Gebirges typisch für eine nicht-kollisionale Orogenese. In den südlichen Zentralanden (SZA, 29-39° S) verändert sich der Subduktionswinkel der ozeanischen Platte zwischen 33 ° S und 35 ° S von fast horizontal (< 5° Einfallen) im Norden zu einem steileren Winkel (~ 30 ° Einfallen) im Süden. Begleitet wird dieser Trend von systematischen, Süd-gerichteten Abnahmen der topographischen Erhebung, der Krusteneinengung und der Vorland- und Orogenbreite, sowie von Variationen im Deformationsstil des Vorlandes, wo die Einengung des Deckgebirges in unterschiedlichem Maße von einer entsprechenden Deformation des Grundgebirges begleitet wird. . Darüber hinaus sind die SZA eine seismisch sehr aktive Region. Die Kontinentalplatte zeichnet sich durch eine relativ flache Seismizität (< 30 km Tiefe) aus, die sich hauptsächlich auf die Übergänge vom Orogen zu den Vorlandbereichen konzentriert; im Gegensatz dazu tritt tiefere Seismizität in den zentralen Bereichen des nördlichen Vorlandes auf. Darüber hinaus ist häufig auftretende Seismizität auch in den flachen Teilen der ozeanischen Platte und im Plattensegment mit flach einfallender Subduktion zwischen 31 ° S und 33 ° S festzustellen. Die beobachtete räumliche Heterogenität der tektonischen und seismischen Deformation in den SZA wurde auf mehrere Ursachen zurückgeführt, darunter Schwankungen der Sedimentmächtigkeit, das Vorhandensein vererbter Strukturen und Veränderungen des Subduktionswinkels der ozeanischen Platte. Es gibt jedoch bislang keine Studie, die den Zusammenhang zwischen der langfristigen rheologischen Konfiguration der SZA und den räumlichen Deformationsmustern untersucht hat. Darüber hinaus wurden die Auswirkungen der Dichte- und Mächtigkeitsvariationen in der kontinentalen Oberplatte und der verschiedenen Subduktionswinkel auf den rheologischen Zustand der Lithosphäre noch nicht grundlegend untersucht. Da die Rheologie von der Gesteinsart, dem Druck und der Temperatur abhängt, ist eine detaillierte Charakterisierung der Zusammensetzung, Struktur und des thermischen Feldes der Lithosphäre erforderlich. Daher habe ich unter Verwendung kombinierter Modellierungsansätze und geophysikalischer Daten die folgenden 3D Modelle für die Lithosphäre der SZA konstruiert: (i) ein auf seismischen Daten basierendes Struktur- und Dichtemodell, das anhand des beobachteten Schwerefeldes validiert wurde; (ii) ein thermisches Modell, das die Umwandlung von Mantelscherwellengeschwindigkeiten in Temperaturen mit Berechnungen des konduktiven Wärmetransports für stationäre Bedingungen in der obersten Lithosphäre (<50 km Tiefe) integriert und durch Temperatur- und Wärmeflussmessungen validiert wurde; und (iii) ein rheologisches Modell der langfristig bedingten Lithosphärenfestigkeit, das auf den zuvor erzeugten Modellen gründet. Die Ergebnisse dieser Dissertation zeigen, dass die thermischen und rheologischen Bedingungen in den heutigen SZA durch verschiedene Mechanismen in unterschiedlichen Tiefen gesteuert werden. In flachen Tiefen (< 50 km) wird das thermomechanische Feld durch die heterogene Zusammensetzung der kontinentalen Lithosphäre differenziert. Eine Überprägung durch die ozeanische Platte ist dort nachweisbar, wo die ozeanische Platte flach (< 85 km tief) und die radiogene Kruste dünn ist, was insgesamt zu niedrigeren Temperaturen und einer höheren Festigkeit im Vergleich zu Bereichen führt, in denen die Platte steil einfällt und die radiogene Kruste dick ist. In Tiefen > 50 km treten die größten Temperaturschwankungen dort auf, wo die subduzierten Platte nachgewiesen wurde, was bedeutet, dass das tiefe thermische Feld den Subduktionswinkel gesteuert wird. Die Ergebnisse dieser Doktorarbeit legen nahe, dass der langfristige thermomechanische Zustand der Lithosphäre die räumliche Verteilung rezenter Seismizität beeinflusst. Der größte Anteil innerhalb der Kontinentalplatte registrierter Erdbebentätigkeit tritt oberhalb des modellierten Übergangs von spröden zu duktilen Bedingungen auf. Außerdem besteht eine räumliche Korrelation zwischen Erdbebenclustern und den Übergängen von den mechanisch rigideren Vorlandbereichen (Forearc und Foreland) zum mechanisch schwächeren Orogen. Demgegenüber wird vermehrte Seismizität innerhalb der ozeanischen Platte auch dort nachgewiesen, wo entsprechend der Modellierung langfristig duktile Bedingungen erwartet werden. Ich habe daher den möglichen Einfluss zusätzlicher Mechanismen untersucht, die ein Auslösen dieser Erdbeben begünstigen könnten, darunter die Kompaktion von Sedimenten an der Subduktionsgrenzfläche und Dehydrationsreaktionen innerhalb der Platte. Dazu habe ich eine qualitative Analyse des Hydratationszustandes des Mantels unter Verwendung des Verhältnisses zwischen Kompressions- und Scherwellengeschwindigkeit (Vp/Vs-Verhältnis aus einemseismischen Tomographiemodell) durchgeführt. Die Ergebnisse dieser Analyse zeigen, dass der Großteil der Seismizität räumlich mit hydratisierten Bereichen in der subduzierten Platte und im darüber liegenden kontinentalen Mantel korreliert, mit Ausnahme eines Erdbebenclusters, das innerhalb des flachen Plattensegments auftritt. In diesem Bereich wechselt die subduzierte Platte von einem flachen in einen steilen Subduktionswinkel und Erdbeben werden wahrscheinlich durch Biegevorgänge in der Platte ausgelöst. Auch die wichtigsten Variationen in den beobachteten tektonischen Mustern scheinen durch die thermomechanische Konfiguration der Lithosphäre beeinflusst zu sein. Die mechanisch starken Bereiche von Forearc und Foreland zeigen aufgrund ihrer Verformungsbeständigkeit geringere Verkürzungsraten als der relativ schwache Bereich des Orogens. Darüber hinaus bestätigen die in dieser Dissertation modellierten strukturellen und thermomechanischen Eigenschaften der Lithosphäre auch frühere Analysen geodynamischer Simulationen, denen zufolge der Deformationsstil im Orogen- und Vorlandbereich jeweils von Variationen in der Lithosphären- und Krustendicke, im Vorhandensein schwacher Sedimente und in der gravitativen potentiellen Energie kontrolliert wird. Eine Sonderstellung nimmt der nordöstliche Vorlandbereich der SZA ein, wo eine verstärkte Seismizität und eine das Deck-und Grundgebirge erfassende Deformation zu beobachten sind, obwohl die modellierte Krustenfestigkeit dort Werte übersteigt, die für die in diesem Gebiet anzunehmenden tektonischen Spannungen typisch wären. . Mechanismen zur Lokalisierung verstärkter Deformation in einem Gebiet beitragen können, das nach den vorliegenden Modellen einer tektonischen Verformung widerstehen sollte, sind: (i) erhöhte tektonische Kräfte durch ein steileres Abtauchen der Platte und (ii) Schwächezonen in der Kruste, die auf prä-andine Deformationsereignisse zurückgehen. Schließlich könnten die thermomechanischen Bedingungen in diesem Teil des Vorlands einchlüsselfaktor für die Erhaltung des flachen Subduktionswinkels in diesen Breiten der SZA sein. KW - Andes KW - Anden KW - subduction KW - Subduktion KW - lithosphere KW - Lithosphäre KW - earthquakes KW - Erdbeben KW - modelling KW - Modellierung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549275 ER - TY - GEN A1 - Roelly, Sylvie A1 - Dai Pra, Paolo T1 - An existence result for infinite-dimensional Brownian diffusions with non- regular and non Markovian drift N2 - We prove in this paper an existence result for infinite-dimensional stationary interactive Brownian diffusions. The interaction is supposed to be small in the norm ||.||∞ but otherwise is very general, being possibly non-regular and non-Markovian. Our method consists in using the characterization of such diffusions as space-time Gibbs fields so that we construct them by space-time cluster expansions in the small coupling parameter. KW - infinite-dimensional Brownian diffusion KW - space-time Gibbs field KW - cluster expansion Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6684 ER - TY - GEN A1 - Roelly, Sylvie A1 - Dereudre, David T1 - Propagation of Gibbsiannes for infinite-dimensional gradient Brownian diffusions N2 - We study the (strong-)Gibbsian character on R Z d of the law at time t of an infinitedimensional gradient Brownian diffusion , when the initial distribution is Gibbsian. KW - infinite-dimensional Brownian diffusion KW - Gibbs measure KW - cluster expansion Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6918 ER - TY - GEN A1 - Roelly, Sylvie A1 - Dereudre, David T1 - On Gibbsianness of infinite-dimensional diffusions N2 - The authors analyse different Gibbsian properties of interactive Brownian diffusions X indexed by the d-dimensional lattice. In the first part of the paper, these processes are characterized as Gibbs states on path spaces. In the second part of the paper, they study the Gibbsian character on R^{Z^d} of the law at time t of the infinite-dimensional diffusion X(t), when the initial law is Gibbsian. AMS Classifications: 60G15 , 60G60 , 60H10 , 60J60 KW - infinite-dimensional Brownian diffusion KW - Gibbs field KW - cluster expansion Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6692 ER - TY - INPR A1 - Roelly, Sylvie A1 - Fradon, Myriam T1 - Infinite system of Brownian balls : equilibrium measures are canonical Gibbs N2 - We consider a system of infinitely many hard balls in Rd undergoing Brownian motions and submitted to a smooth pair potential. It is modelized by an infinite-dimensional stochastic differential equation with a local time term. We prove that the set of all equilibrium measures, solution of a detailed balance equation, coincides with the set of canonical Gibbs measures associated to the hard core potential added to the smooth interaction potential. KW - Stochastic Differential Equation KW - hard core potential KW - Canonical Gibbs measure KW - detailed balance equation KW - reversible measure Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6720 ER - TY - GEN A1 - Roelly, Sylvie A1 - Sortais, Michel T1 - Space-time asymptotics of an infinite-dimensional diffusion having a long- range memory N2 - We develop a cluster expansion in space-time for an infinite-dimensional system of interacting diffusions where the drift term of each diffusion depends on the whole past of the trajectory; these interacting diffusions arise when considering the Langevin dynamics of a ferromagnetic system submitted to a disordered external magnetic field. KW - Random Field Ising Model KW - Langevin Dynamics KW - Interacting Diffusion Processes KW - Space-Time Cluster Expansions Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6700 ER - TY - GEN A1 - Roelly, Sylvie A1 - Thieullen, Michèle T1 - Duality formula for the bridges of a Brownian diffusion : application to gradient drifts N2 - In this paper, we consider families of time Markov fields (or reciprocal classes) which have the same bridges as a Brownian diffusion. We characterize each class as the set of solutions of an integration by parts formula on the space of continuous paths C[0; 1]; R-d) Our techniques provide a characterization of gradient diffusions by a duality formula and, in case of reversibility, a generalization of a result of Kolmogorov. KW - reciprocal processes KW - stochastic bridge KW - mixture of bridges KW - integration by parts formula KW - Malliavin calculus KW - entropy KW - time reversal Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6710 ER - TY - THES A1 - Rolo, David T1 - Assembly of photosystem I in thylakoid membranes T1 - Die Assemblierung des Photosystems I in der Thylakoidmembran N2 - The light reactions of photosynthesis are carried out by a series of multiprotein complexes embedded in thylakoid membranes. Among them, photosystem I (PSI), acting as plastocyanin-ferderoxin oxidoreductase, catalyzes the final reaction. Together with light-harvesting antenna I, PSI forms a high-molecular-weight supercomplex of ~600 kDa, consisting of eighteen subunits and nearly two hundred co-factors. Assembly of the various components into a functional thylakoid membrane complex requires precise coordination, which is provided by the assembly machinery. Although this includes a small number of proteins (PSI assembly factors) that have been shown to play a role in the formation of PSI, the process as a whole, as well as the intricacy of its members, remains largely unexplored. In the present work, two approaches were used to find candidate PSI assembly factors. First, EnsembleNet was used to select proteins thought to be functionally related to known PSI assembly factors in Arabidopsis thaliana (approach I), and second, co-immunoprecipitation (Co-IP) of tagged PSI assembly factors in Nicotiana tabacum was performed (approach II). Here, the novel PSI assembly factors designated CO-EXPRESSED WITH PSI ASSEMBLY 1 (CEPA1) and Ycf4-INTERACTING PROTEIN 1 (Y4IP1) were identified. A. thaliana null mutants for CEPA1 and Y4IP1 showed a growth phenotype and pale leaves compared with the wild type. Biophysical experiments using pulse amplitude modulation (PAM) revealed insufficient electron transport on the PSII acceptor side. Biochemical analyses revealed that both CEPA1 and Y4IP1 are specifically involved in PSI accumulation in A. thaliana at the post-translational level but are not essential. Consistent with their roles as factors in the assembly of a thylakoid membrane protein complex, the two proteins localize to thylakoid membranes. Remarkably, cepa1 y4ip1 double mutants exhibited lethal phenotypes in early developmental stages under photoautotrophic growth. Finally, co-IP and native gel experiments supported a possible role for CEPA1 and Y4IP1 in mediating PSI assembly in conjunction with other PSI assembly factors (e.g., PPD1- and PSA3-CEPA1 and Ycf4-Y4IP1). The fact that CEPA1 and Y4IP1 are found exclusively in green algae and higher plants suggests eukaryote-specific functions. Although the specific mechanisms need further investigation, CEPA1 and Y4IP1 are two novel assembly factors that contribute to PSI formation. N2 - Die Lichtreaktionen der Photosynthese werden von einer Reihe von Multiproteinkomplexen durchgeführt, die in Thylakoidmembranen eingebettet sind. Hier katalysiert das Photosystem I (PSI), das als Plastocyanin-Ferderoxin-Oxidoreduktase fungiert, die letzte Reaktion. Zusammen mit der lichtsammelnden Antenne I bildet PSI einen hochmolekularen Superkomplex von etwa 600 kDa, der aus achtzehn Untereinheiten und fast zweihundert Co-Faktoren besteht. Der Zusammenbau der verschiedenen Komponenten zu einem funktionsfähigen Thylakoidmembrankomplex erfordert eine präzise Koordination, die durch den Assemblierungsapparat gewährleistet wird. Obwohl dieser eine kleine Anzahl von Proteinen (PSI-Assemblierungsfaktoren) umfasst, die nachweislich eine Rolle bei der Bildung des PSI spielen, ist der Prozess als Ganzes sowie die Komplexität seiner Mitglieder noch weitgehend unerforscht. In der vorliegenden Arbeit wurden zwei Ansätze verwendet, um Kandidaten für PSI-Assemblierungsfaktoren zu finden. Erstens wurde EnsembleNet verwendet, um Proteine auszuwählen, von denen angenommen wird, dass sie funktionell mit bekannten PSI-Assemblierungsfaktoren in Arabidopsis thaliana verwandt sind (Ansatz I), und zweitens wurde eine Co-Immunopräzipitation (Co-IP) von markierten PSI-Assemblierungsfaktoren in Nicotiana tabacum durchgeführt (Ansatz II). Dabei wurden die neuartigen PSI-Assemblierungsfaktoren mit der Bezeichnung CO-EXPRESSED WITH PSI ASSEMBLY 1 (CEPA1) und Ycf4-INTERACTING PROTEIN 1 (Y4IP1) identifiziert. A. thaliana Nullmutanten für CEPA1 und Y4IP1 zeigten einen Wachstumsphänotyp und blasse Blätter im Vergleich zum Wildtyp. Biophysikalische Experimente unter Verwendung der Pulsamplitudenmodulation (PAM) zeigten einen unzureichenden Elektronentransport auf der PSII-Akzeptorseite. Biochemische Analysen ergaben, dass sowohl CEPA1 als auch Y4IP1 spezifisch an der PSI-Akkumulation in A. thaliana auf posttranslationaler Ebene beteiligt, jedoch nicht essentiell sind. Entsprechend ihrer Rolle als Faktoren für den Aufbau eines Thylakoidmembran-Proteinkomplexes sind die beiden Proteine an Thylakoidmembranen lokalisiert. Bemerkenswerterweise wiesen cepa1 y4ip1-Doppelmutanten in frühen Entwicklungsstadien unter photoautotrophem Wachstum tödliche Phänotypen auf. Schließlich untermauerten Co-IP- und native Gelexperimente eine mögliche Rolle von CEPA1 und Y4IP1 bei der Vermittlung des PSI-Aufbaus in Verbindung mit anderen PSI-Aufbaufaktoren (z. B. PPD1- und PSA3-CEPA1, und Ycf4-Y4IP1). Die Tatsache, dass CEPA1 und Y4IP1 ausschließlich in Grünalgen und höheren Pflanzen vorkommen, lässt auf eukaryontenspezifische Funktionen schließen. Obwohl die spezifischen Mechanismen noch weiter untersucht werden müssen, sind CEPA1 und Y4IP1 zwei neuartige Assemblierungsfaktoren, die zur PSI-Bildung beitragen. KW - photosynthesis KW - photosystem I KW - biogenesis KW - thylakoid membranes KW - assembly factor KW - Photosynthese KW - Photosystem I KW - Biogenese KW - Thylakoidmembran KW - Assemblierungsfaktor Y1 - 2023 ER - TY - CHAP A1 - Romero, G. E. A1 - Owocki, S. P. A1 - Araudo, A. T. A1 - Townsend, R. H. D. A1 - Benaglia, P. T1 - Using gamma-rays to probe the clumped structure of stellar winds N2 - Gamma-rays can be produced by the interaction of a relativistic jet and the matter of the stellar wind in the subclass of massive X-ray binaries known as “microquasars”. The relativistic jet is ejected from the surroundings of the compact object and interacts with cold protons from the stellar wind, producing pions that then quickly decay into gamma-rays. Since the resulting gamma-ray emissivity depends on the target density, the detection of rapid variability in microquasars with GLAST and the new generation of Cherenkov imaging arrays could be used to probe the clumped structure of the stellar wind. In particular, we show here that the relative fluctuation in gamma rays may scale with the square root of the ratio of porosity length to binary separation, $\sqrt{h/a}$, implying for example a ca. 10% variation in gamma ray emission for a quite moderate porosity, h/a ∼ 0.01. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18210 ER - TY - JOUR A1 - Rose, Robert A1 - Groeger, Lars A1 - Hölzle, Katharina T1 - The Emergence of Shared Leadership in Innovation Labs JF - Frontiers in Psychology N2 - Implementing innovation laboratories to leverage intrapreneurship are an increasingly popular organizational practice. A typical feature in these creative environments are semi-autonomous teams in which multiple members collectively exert leadership influence, thereby challenging traditional command-and-control conceptions of leadership. An extensive body of research on the team-centric concept of shared leadership has recognized the potential for pluralized leadership structures in enhancing team effectiveness; however, little empirical work has been conducted in organizational contexts in which creativity is key. This study set out to explore antecedents of shared leadership and its influence on team creativity in an innovation lab. Building on extant shared leadership and innovation research, we propose antecedents customary to creative teamwork, that is, experimental culture, task reflexivity, and voice. Multisource data were collected from 104 team members and 49 evaluations of 29 coaches nested in 21 teams working in a prototypical innovation lab. We identify factors specific to creative teamwork that facilitate the emergence of shared leadership by providing room for experimentation, encouraging team members to speak up in the creative process, and cultivating a reflective application of entrepreneurial thinking. We provide specific exemplary activities for innovation lab teams to increase levels of shared leadership. KW - innovation laboratories KW - intrapreneurship KW - team creativity KW - shared leadership KW - social network analysis Y1 - 2021 U6 - https://doi.org/10.3389/fpsyg.2021.685167 SN - 1664-1078 VL - 12 SP - 1 EP - 13 PB - Frontiers in psychology CY - Lausanne, Schweiz ER - TY - JOUR A1 - Rosenblum, Michael A1 - Pikovskij, Arkadij A1 - Kühn, Andrea A. A1 - Busch, Johannes Leon T1 - Real-time estimation of phase and amplitude with application to neural data JF - Scientific reports N2 - Computation of the instantaneous phase and amplitude via the Hilbert Transform is a powerful tool of data analysis. This approach finds many applications in various science and engineering branches but is not proper for causal estimation because it requires knowledge of the signal’s past and future. However, several problems require real-time estimation of phase and amplitude; an illustrative example is phase-locked or amplitude-dependent stimulation in neuroscience. In this paper, we discuss and compare three causal algorithms that do not rely on the Hilbert Transform but exploit well-known physical phenomena, the synchronization and the resonance. After testing the algorithms on a synthetic data set, we illustrate their performance computing phase and amplitude for the accelerometer tremor measurements and a Parkinsonian patient’s beta-band brain activity. Y1 - 2021 U6 - https://doi.org/10.1038/s41598-021-97560-5 SN - 2045-2322 VL - 11 PB - Springer Nature CY - London ER - TY - CHAP A1 - Rossmanith, Eva A1 - Blaum, Niels A1 - Keil, Manfred A1 - Langerwisch, F. A1 - Meyer, Jork A1 - Popp, Alexander A1 - Schmidt, Michael A1 - Schultz, Christoph A1 - Schwager, Monika A1 - Vogel, Melanie A1 - Wasiolka, Bernd A1 - Jeltsch, Florian T1 - Scaling up local population dynamics to regional scales BT - an integrated approach N2 - In semi-arid savannas, unsustainable land use can lead to degradation of entire landscapes, e.g. in the form of shrub encroachment. This leads to habitat loss and is assumed to reduce species diversity. In BIOTA phase 1, we investigated the effects of land use on population dynamics on farm scale. In phase 2 we scale up to consider the whole regional landscape consisting of a diverse mosaic of farms with different historic and present land use intensities. This mosaic creates a heterogeneous, dynamic pattern of structural diversity at a large spatial scale. Understanding how the region-wide dynamic land use pattern affects the abundance of animal and plant species requires the integration of processes on large as well as on small spatial scales. In our multidisciplinary approach, we integrate information from remote sensing, genetic and ecological field studies as well as small scale process models in a dynamic region-wide simulation tool.
Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006. Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7320 N1 - [Poster] ER - TY - JOUR A1 - Rowe, John Carlos T1 - Disease, culture, and transnationalism in the Americas JF - Mobilisierte Kulturen Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57345 SN - 2192-3019 SN - 2192-3027 IS - 1 SP - 71 EP - 87 ER - TY - THES A1 - Ruch, Joël T1 - Volcano deformation analysis in the Lazufre area (central Andes) using geodetic and geological observations T1 - Vulkan Deformationsanalyse im Bereich Lazufre (Zentral-Anden) mit geodätischen und geologischen Beobachtungen N2 - Large-scale volcanic deformation recently detected by radar interferometry (InSAR) provides new information and thus new scientific challenges for understanding volcano-tectonic activity and magmatic systems. The destabilization of such a system at depth noticeably affects the surrounding environment through magma injection, ground displacement and volcanic eruptions. To determine the spatiotemporal evolution of the Lazufre volcanic area located in the central Andes, we combined short-term ground displacement acquired by InSAR with long-term geological observations. Ground displacement was first detected using InSAR in 1997. By 2008, this displacement affected 1800 km2 of the surface, an area comparable in size to the deformation observed at caldera systems. The original displacement was followed in 2000 by a second, small-scale, neighbouring deformation located on the Lastarria volcano. We performed a detailed analysis of the volcanic structures at Lazufre and found relationships with the volcano deformations observed with InSAR. We infer that these observations are both likely to be the surface expression of a long-lived magmatic system evolving at depth. It is not yet clear whether Lazufre may trigger larger unrest or volcanic eruptions; however, the second deformation detected at Lastarria and the clear increase of the large-scale deformation rate make this an area of particular interest for closer continuous monitoring. N2 - Vulkanische Deformationen in großem Maßstab, die mittels InSAR gemessen wurden, liefern neue Informationen und dadurch einen neuen Blickwinkel auf vulkan-tektonische Aktivitäten und das Verständnis von langlebigen, magmatischen Systemen. Die Destabilisierung eines solchen Systems in der Tiefe beeinflusst dauerhaft die Oberfläche durch Versatz des Bodens, magmatische Einflüsse und vulkanische Unruhen. Mit der Kombination aus kleinräumigem Bodenversatz gemessen mittels InSAR, numerischer Modellierung und langfristigen geologischen Beobachtungen, analysieren wir die Gegend um den Vulkan Lazufre in den Zentralanden, um die raumzeitliche Entwicklung der Region zu bestimmen. Bodenversatz wurde hierbei im Jahr 1997 mittels Radar-Interferrometrie (InSAR) gemessen, was eine Fläche von 1800 km² ausmacht, vergleichbar mit der Größe der Deformation des Kraters. Im Jahr 2000 wurde zusätzlich eine kleinräumige Deformation am Nachbarvulkan Lastarria entdeckt. Wir sehen räumliche als auch zeitliche Verbindungen zwischen der Deformation des Vulkans und vulkanischen Strukturen innerhalb der betroffenen Gegend. Wir folgern daraus, dass diese Beobachtungen der Ausdruck eines langlebigen, magmatischen Systems in der Tiefe an der Oberfläche sind. Es ist noch nicht klar, ob Lazufre größere vulkanische Unruhen, wie zum Beispiel Eruptionen auslösen könnte, aber die Deformation am Vulkan Lastarria und ein Anstieg der großräumigen Deformationsrate, machen diese Region interessant für eine zukünftige, kontinuierliche Überwachung. KW - Vulkan Verformung KW - InSAR KW - zentralen Anden KW - Spannungsfeld KW - volcano deformation KW - InSAR KW - central Andes KW - stress field Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-47361 ER - TY - THES A1 - Ruiz Rodriguez, Janete Lorena T1 - Osmotic pressure effects on collagen mimetic peptides N2 - Collagen is the most abundant protein in mammals. In many tissues, collagen molecules assemble to form a hierarchical structure. In the smallest supramolecular unit, named fibril, each molecule is displaced in the axial direction with respect to its neighbors. This staggering creates a periodic gap and overlap regions, where the gap regions exhibit 20% less density. These fibril-forming collagens play an essential role in the strength of connective tissues. Despite much effort, directed at understanding collagen function and regulation, the influence of the chemical environment on the local structural and mechanical properties remains poorly understood. Recent studies, aimed at elucidating the effect of osmotic pressure, showed that collagen contracts upon water removal. This observation highlights the importance of water for the stabilization and mechanics of the collagen molecule. Using collagen mimetic peptides (CMPs), which fold into triple helical structures reminiscent of natural collagen, the primary goal of this work was to investigate the effect of the osmotic pressure on specific collagen-mimetic sequences. CMPs were used as the model system as they provide sequence control, which is essential for discriminating local from global structural changes and for relating the observed effects to existing knowledge about the full-length collagen molecule. Of specific interest was the structure of individual collagen triple helices as well as their organization into self-assembled higher order structures. These key structural features were monitored with infrared spectroscopy (IR) and synchrotron X-ray scattering, while varying the osmotic pressure. For controlling the osmotic pressure, CMP powder samples were incubated in air of defined relative humidity, ranging from dry conditions to highly “humid”. In addition, to obtain more biologically relevant conditions, the CMPs were measured in ultrapure water and in solutions containing small molecule osmolytes. Using the sequences (Pro-Pro-Gly)10, (Pro-Hyp-Gly)10 and (Hyp-Hyp-Gly)10, it was shown that CMPs with different degrees of proline hydroxylation (Hyp = hydroxyproline) exhibit a sequence-specific response to osmotic pressure. IR spectroscopy revealed that osmotic pressure changes affect the strength of the triple helix stabilizing, interchain hydrogen bond and that the extent of this change depends on the degree of hydroxylation. X-ray scattering experiments further showed that changes in osmotic pressure affect both the molecular length as well as the higher order organization of CMPs. Starting from a pseudo-hexagonal packing in the dry state, all three CMPs showed isotropic swelling when increasing the water content to approximately 1.2 water molecules per amino acid, again to different extents depending on the degree of hydroxylation. When increasing the water content further, this pseudo-hexagonal arrangement breaks down. In the fully hydrated state, each CMP is characterized by its own specific and more complex packing geometry. While these changes in the lateral packing arrangement suggest swelling upon hydration, an overall decrease of the molecular length (i.e. contraction) was observed in the axial direction. Also for this structural feature, a strong dependency on the specific amino acid sequence was found. Interestingly, the observed contraction is the opposite of what has been reported for natural collagen. As (Pro-Pro-Gly)n, (Pro-Hyp-Gly)n and (Hyp-Hyp-Gly)n repeat units are found in collagen with a relatively high abundance, this suggests that other collagen sequence fragments need to respond to hydration in the opposite way to obtain a net elongation of the full-length collagen molecule. To test this hypothesis, sequences predicted to be sensitive to osmotic pressure were considered. One such sequence, consisting of two repeat units (Ala-Arg-Gly-Ser-Asp-Gly), was inserted as a guest into a (Pro-Pro-Gly) host. When compared to the canonical CMP sequences investigated earlier, the lateral helix packing follows a similar trend with increasing hydration; however, the host-guest CMP axially elongates with increasing water content. This behavior is more similar to what has been found for natural collagen and suggests that different sequences do determine the molecular length of collagen sequences differently. Interestingly, the canonical sequences are more abundant in the overlap region while the guest sequence is found in the gap region. This allows to speculate that sequences in the gap and overlap regions possess a specifically fine-tuned local response to osmotic pressure changes. Clearly, more experiments with additional sequences are needed to confirm this. In conclusion, the results obtained in this work indicate a highly sequence specific interaction between collagen and water. Osmotic pressure-induced conformational changes mostly originate from local geometries and bonding patterns and affect both the structure of individual triple helices as well as higher order assemblies. One key remaining question is how these conformational changes affect the local mechanical properties of the collagen molecule. As a first step, the stiffness (persistence length) of full-length collagen was determined using atomic force microscopy. In the future, experimental strategies need to be developed that allow for investigating the mechanical properties of specific collagen sequences, e.g. performing single-molecule force spectroscopy of CMPs. Y1 - 2019 ER - TY - CHAP A1 - Runacres, M. C. T1 - Hydrodynamical models of clumping beyond 50 R∗ N2 - We present one-dimensional, time-dependent models of the clumps generated by the linedeshadowing instability. In order to follow the clumps out to distances of more than 1000 R∗, we use an efficient moving-box technique. We show that, within the approximations, the wind can remain clumped well into the formation region of the radio continuum. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18030 ER - TY - THES A1 - Rust, Henning T1 - Detection of long-range dependence : applications in climatology and hydrology T1 - Detektion langreichweitiger Korrelationen : Anwendungen in Klimatologie und Hydrologie N2 - It is desirable to reduce the potential threats that result from the variability of nature, such as droughts or heat waves that lead to food shortage, or the other extreme, floods that lead to severe damage. To prevent such catastrophic events, it is necessary to understand, and to be capable of characterising, nature's variability. Typically one aims to describe the underlying dynamics of geophysical records with differential equations. There are, however, situations where this does not support the objectives, or is not feasible, e.g., when little is known about the system, or it is too complex for the model parameters to be identified. In such situations it is beneficial to regard certain influences as random, and describe them with stochastic processes. In this thesis I focus on such a description with linear stochastic processes of the FARIMA type and concentrate on the detection of long-range dependence. Long-range dependent processes show an algebraic (i.e. slow) decay of the autocorrelation function. Detection of the latter is important with respect to, e.g. trend tests and uncertainty analysis. Aiming to provide a reliable and powerful strategy for the detection of long-range dependence, I suggest a way of addressing the problem which is somewhat different from standard approaches. Commonly used methods are based either on investigating the asymptotic behaviour (e.g., log-periodogram regression), or on finding a suitable potentially long-range dependent model (e.g., FARIMA[p,d,q]) and test the fractional difference parameter d for compatibility with zero. Here, I suggest to rephrase the problem as a model selection task, i.e.comparing the most suitable long-range dependent and the most suitable short-range dependent model. Approaching the task this way requires a) a suitable class of long-range and short-range dependent models along with suitable means for parameter estimation and b) a reliable model selection strategy, capable of discriminating also non-nested models. With the flexible FARIMA model class together with the Whittle estimator the first requirement is fulfilled. Standard model selection strategies, e.g., the likelihood-ratio test, is for a comparison of non-nested models frequently not powerful enough. Thus, I suggest to extend this strategy with a simulation based model selection approach suitable for such a direct comparison. The approach follows the procedure of a statistical test, with the likelihood-ratio as the test statistic. Its distribution is obtained via simulations using the two models under consideration. For two simple models and different parameter values, I investigate the reliability of p-value and power estimates obtained from the simulated distributions. The result turned out to be dependent on the model parameters. However, in many cases the estimates allow an adequate model selection to be established. An important feature of this approach is that it immediately reveals the ability or inability to discriminate between the two models under consideration. Two applications, a trend detection problem in temperature records and an uncertainty analysis for flood return level estimation, accentuate the importance of having reliable methods at hand for the detection of long-range dependence. In the case of trend detection, falsely concluding long-range dependence implies an underestimation of a trend and possibly leads to a delay of measures needed to take in order to counteract the trend. Ignoring long-range dependence, although present, leads to an underestimation of confidence intervals and thus to an unjustified belief in safety, as it is the case for the return level uncertainty analysis. A reliable detection of long-range dependence is thus highly relevant in practical applications. Examples related to extreme value analysis are not limited to hydrological applications. The increased uncertainty of return level estimates is a potentially problem for all records from autocorrelated processes, an interesting examples in this respect is the assessment of the maximum strength of wind gusts, which is important for designing wind turbines. The detection of long-range dependence is also a relevant problem in the exploration of financial market volatility. With rephrasing the detection problem as a model selection task and suggesting refined methods for model comparison, this thesis contributes to the discussion on and development of methods for the detection of long-range dependence. N2 - Die potentiellen Gefahren und Auswirkungen der natürlicher Klimavariabilitäten zu reduzieren ist ein wünschenswertes Ziel. Solche Gefahren sind etwa Dürren und Hitzewellen, die zu Wasserknappheit führen oder, das andere Extrem, Überflutungen, die einen erheblichen Schaden an der Infrastruktur nach sich ziehen können. Um solche katastrophalen Ereignisse zu vermeiden, ist es notwendig die Dynamik der Natur zu verstehen und beschreiben zu können. Typischerweise wird versucht die Dynamik geophysikalischer Datenreihen mit Differentialgleichungssystemen zu beschreiben. Es gibt allerdings Situationen in denen dieses Vorgehen nicht zielführend oder technisch nicht möglich ist. Dieses sind Situationen in denen wenig Wissen über das System vorliegt oder es zu komplex ist um die Modellparameter zu identifizieren. Hier ist es sinnvoll einige Einflüsse als zufällig zu betrachten und mit Hilfe stochastischer Prozesse zu modellieren. In dieser Arbeit wird eine solche Beschreibung mit linearen stochastischen Prozessen der FARIMA-Klasse angestrebt. Besonderer Fokus liegt auf der Detektion von langreichweitigen Korrelationen. Langreichweitig korrelierte Prozesse sind solche mit einer algebraisch, d.h. langsam, abfallenden Autokorrelationsfunktion. Eine verläßliche Erkennung dieser Prozesse ist relevant für Trenddetektion und Unsicherheitsanalysen. Um eine verläßliche Strategie für die Detektion langreichweitig korrelierter Prozesse zur Verfügung zu stellen, wird in der Arbeit ein anderer als der Standardweg vorgeschlagen. Gewöhnlich werden Methoden eingesetzt, die das asymptotische Verhalten untersuchen, z.B. Regression im Periodogramm. Oder aber es wird versucht ein passendes potentiell langreichweitig korreliertes Modell zu finden, z.B. aus der FARIMA Klasse, und den geschätzten fraktionalen Differenzierungsparameter d auf Verträglichkeit mit dem trivialen Wert Null zu testen. In der Arbeit wird vorgeschlagen das Problem der Detektion langreichweitiger Korrelationen als Modellselektionsproblem umzuformulieren, d.h. das beste kurzreichweitig und das beste langreichweitig korrelierte Modell zu vergleichen. Diese Herangehensweise erfordert a) eine geeignete Klasse von lang- und kurzreichweitig korrelierten Prozessen und b) eine verläßliche Modellselektionsstrategie, auch für nichtgenestete Modelle. Mit der flexiblen FARIMA-Klasse und dem Whittleschen Ansatz zur Parameterschätzung ist die erste Voraussetzung erfüllt. Hingegen sind standard Ansätze zur Modellselektion, wie z.B. der Likelihood-Ratio-Test, für nichtgenestete Modelle oft nicht trennscharf genug. Es wird daher vorgeschlagen diese Strategie mit einem simulationsbasierten Ansatz zu ergänzen, der insbesondere für die direkte Diskriminierung nichtgenesteter Modelle geeignet ist. Der Ansatz folgt einem statistischen Test mit dem Quotienten der Likelihood als Teststatistik. Ihre Verteilung wird über Simulationen mit den beiden zu unterscheidenden Modellen ermittelt. Für zwei einfache Modelle und verschiedene Parameterwerte wird die Verläßlichkeit der Schätzungen für p-Wert und Power untersucht. Das Ergebnis hängt von den Modellparametern ab. Es konnte jedoch in vielen Fällen eine adäquate Modellselektion etabliert werden. Ein wichtige Eigenschaft dieser Strategie ist, dass unmittelbar offengelegt wird, wie gut sich die betrachteten Modelle unterscheiden lassen. Zwei Anwendungen, die Trenddetektion in Temperaturzeitreihen und die Unsicherheitsanalyse für Bemessungshochwasser, betonen den Bedarf an verläßlichen Methoden für die Detektion langreichweitiger Korrelationen. Im Falle der Trenddetektion führt ein fälschlicherweise gezogener Schluß auf langreichweitige Korrelationen zu einer Unterschätzung eines Trends, was wiederum zu einer möglicherweise verzögerten Einleitung von Maßnahmen führt, die diesem entgegenwirken sollen. Im Fall von Abflußzeitreihen führt die Nichtbeachtung von vorliegenden langreichweitigen Korrelationen zu einer Unterschätzung der Unsicherheit von Bemessungsgrößen. Eine verläßliche Detektion von langreichweitig Korrelierten Prozesse ist somit von hoher Bedeutung in der praktischen Zeitreihenanalyse. Beispiele mit Bezug zu extremem Ereignissen beschränken sich nicht nur auf die Hochwasseranalyse. Eine erhöhte Unsicherheit in der Bestimmung von extremen Ereignissen ist ein potentielles Problem von allen autokorrelierten Prozessen. Ein weiteres interessantes Beispiel ist hier die Abschätzung von maximalen Windstärken in Böen, welche bei der Konstruktion von Windrädern eine Rolle spielt. Mit der Umformulierung des Detektionsproblems als Modellselektionsfrage und mit der Bereitstellung geeigneter Modellselektionsstrategie trägt diese Arbeit zur Diskussion und Entwicklung von Methoden im Bereich der Detektion von langreichweitigen Korrelationen bei. KW - langreichweitige Korrelationen KW - nichtgenestete Modellselektion KW - FARIMA KW - Unsicherheitsanalyse KW - Bemessungshochwasser KW - long-range dependence KW - long-memory KW - non-nested model selection KW - FARIMA KW - uncertainty analysis KW - return level estimation Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13347 ER - TY - JOUR A1 - Rösler, Antonia A1 - Gasparatos, Nikolaos A1 - Hermanussen, Michael A1 - Scheffler, Christiane T1 - Practicability and user-friendliness of height measurements by proof of concept APP using Augmented Reality, in 22 healthy children JF - Human biology and public health N2 - Background: Child growth is a dynamic process. When measured at short intervals, children’s growth shows characteristic patterns that can be of great importance for clinical purposes. Objective: To study whether measuring height on a daily basis using an APP is practicable and user-friendly. Methods: Recruitment took place via Snowball Sampling. Thirteen out of 14 contacted families signed up for a study period of 12 weeks with altogether 22 healthy children aged 3 to 13 years (response rate 93%). The study started with a visit to the family home for the setup of the measurement site, conventional height measuring and initial training of the new measurement process. Follow-up appointments were made at four, eight and 12 weeks. The children’s height was measured at daily intervals at their family homes over a period of three months. Results: The parents altogether recorded 1704 height measurements and meticulously documented practicability and problems when using the device. A 93% response rate in recruitment was achieved by maintaining a high motivation within the families. Contact with the principal investigator was permanently available, including open communication, personal training and attendance during the appointments at the family homes. Conclusion: Measuring height by photographic display is interesting for children and parents and can be used for height measurements at home. A positive response rate of 13 out of 14 families with altogether 22 children highlights feasible recruitment and the high convenience and user-friendliness of daily APP-supported height measurements. Daily APP measurements appear to be a promising new tool for longitudinal growth studies. KW - body height KW - guideline KW - augmented reality KW - daily home-made measurements KW - iPhone KW - APP Y1 - 2022 U6 - https://doi.org/10.52905/hbph2022.2.48 SN - 2748-9957 VL - 2022 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Rösler, Antonia A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - No evidence of growth impairment after forced migration in Polish school children after World War II JF - Human biology and public health N2 - Background: Migration is omnipresent. It can come hand in hand with emotional stress which is known to influence the growth of children. Objective: The aim of this study was to analyse whether type of migration (forced or voluntary) and the geographic direction had influenced the growth of Polish children after World War II. Sample and Methods: A sub dataset of 2,208 individuals between the ages of 2-20, created from data of the 2nd Polish Anthropological Survey carried out in 1966–1969, including anthropometrical data and social and demographic information based on questionnaire, was used to analyse migration effects. Results: No association could be found between the direction of migration and the height of the children. The confidence intervals of the means of all classified migration categories overlap significantly and the effect size of the influence of migration category on height is ds=.140, which is too low to see any effects, even if there were one. Conclusion: Neither forced nor voluntary migration in Poland after World War II led to a change in height in children of migrating families. KW - nutrition KW - stunting KW - socioeconomy KW - education KW - secular changes KW - pubertal timing Y1 - 2023 U6 - https://doi.org/10.52905/hbph2023.1.68 SN - 2748-9957 VL - 1 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Röthlisberger, Livia T1 - Transformative Justice in South Sudan BT - The Transformative Potential of a Contextualized Transitional Justice Process JF - Transitional Justice : Theoretical and Practical Approaches (Potsdamer Studien zu Staat, Recht und Politik ; 7) N2 - This chapter takes the ongoing conflict in South Sudan as a starting point for assessing the concept of transitional justice as such and its implementation in the country in particular. Following a brief description of the conflict and the peace processes, the author sheds light on the shortcomings of the established concept of transitional justice in the situation at hand. Then, the author outlines the alternate concept of transformational justice und takes a closer look at its implications on the situation in South Sudan. The author highlights existing initiatives of transformative justice and is very much in favour of their victim-centered approach. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-570480 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 SP - 167 EP - 191 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Rözer, Viktor T1 - Pluvial flood loss to private households T1 - Schäden durch urbane Sturzfluten in Privathaushalten N2 - Today, more than half of the world’s population lives in urban areas. With a high density of population and assets, urban areas are not only the economic, cultural and social hubs of every society, they are also highly susceptible to natural disasters. As a consequence of rising sea levels and an expected increase in extreme weather events caused by a changing climate in combination with growing cities, flooding is an increasing threat to many urban agglomerations around the globe. To mitigate the destructive consequences of flooding, appropriate risk management and adaptation strategies are required. So far, flood risk management in urban areas is almost exclusively focused on managing river and coastal flooding. Often overlooked is the risk from small-scale rainfall-triggered flooding, where the rainfall intensity of rainstorms exceeds the capacity of urban drainage systems, leading to immediate flooding. Referred to as pluvial flooding, this flood type exclusive to urban areas has caused severe losses in cities around the world. Without further intervention, losses from pluvial flooding are expected to increase in many urban areas due to an increase of impervious surfaces compounded with an aging drainage infrastructure and a projected increase in heavy precipitation events. While this requires the integration of pluvial flood risk into risk management plans, so far little is known about the adverse consequences of pluvial flooding due to a lack of both detailed data sets and studies on pluvial flood impacts. As a consequence, methods for reliably estimating pluvial flood losses, needed for pluvial flood risk assessment, are still missing. Therefore, this thesis investigates how pluvial flood losses to private households can be reliably estimated, based on an improved understanding of the drivers of pluvial flood loss. For this purpose, detailed data from pluvial flood-affected households was collected through structured telephone- and web-surveys following pluvial flood events in Germany and the Netherlands. Pluvial flood losses to households are the result of complex interactions between impact characteristics such as the water depth and a household’s resistance as determined by its risk awareness, preparedness, emergency response, building properties and other influencing factors. Both exploratory analysis and machine-learning approaches were used to analyze differences in resistance and impacts between households and their effects on the resulting losses. The comparison of case studies showed that the awareness around pluvial flooding among private households is quite low. Low awareness not only challenges the effective dissemination of early warnings, but was also found to influence the implementation of private precautionary measures. The latter were predominately implemented by households with previous experience of pluvial flooding. Even cases where previous flood events affected a different part of the same city did not lead to an increase in preparedness of the surveyed households, highlighting the need to account for small-scale variability in both impact and resistance parameters when assessing pluvial flood risk. While it was concluded that the combination of low awareness, ineffective early warning and the fact that only a minority of buildings were adapted to pluvial flooding impaired the coping capacities of private households, the often low water levels still enabled households to mitigate or even prevent losses through a timely and effective emergency response. These findings were confirmed by the detection of loss-influencing variables, showing that cases in which households were able to prevent any loss to the building structure are predominately explained by resistance variables such as the household’s risk awareness, while the degree of loss is mainly explained by impact variables. Based on the important loss-influencing variables detected, different flood loss models were developed. Similar to flood loss models for river floods, the empirical data from the preceding data collection was used to train flood loss models describing the relationship between impact and resistance parameters and the resulting loss to building structures. Different approaches were adapted from river flood loss models using both models with the water depth as only predictor for building structure loss and models incorporating additional variables from the preceding variable detection routine. The high predictive errors of all compared models showed that point predictions are not suitable for estimating losses on the building level, as they severely impair the reliability of the estimates. For that reason, a new probabilistic framework based on Bayesian inference was introduced that is able to provide predictive distributions instead of single loss estimates. These distributions not only give a range of probable losses, they also provide information on how likely a specific loss value is, representing the uncertainty in the loss estimate. Using probabilistic loss models, it was found that the certainty and reliability of a loss estimate on the building level is not only determined by the use of additional predictors as shown in previous studies, but also by the choice of response distribution defining the shape of the predictive distribution. Here, a mix between a beta and a Bernoulli distribution to account for households that are able to prevent losses to their building’s structure was found to provide significantly more certain and reliable estimates than previous approaches using Gaussian or non-parametric response distributions. The successful model transfer and post-event application to estimate building structure loss in Houston, TX, caused by pluvial flooding during Hurricane Harvey confirmed previous findings, and demonstrated the potential of the newly developed multi-variable beta model for future risk assessments. The highly detailed input data set constructed from openly available data sources containing over 304,000 affected buildings in Harris County further showed the potential of data-driven, building-level loss models for pluvial flood risk assessment. In conclusion, pluvial flood losses to private households are the result of complex interactions between impact and resistance variables, which should be represented in loss models. The local occurrence of pluvial floods requires loss estimates on high spatial resolutions, i.e. on the building level, where losses are variable and uncertainties are high. Therefore, probabilistic loss estimates describing the uncertainty of the estimate should be used instead of point predictions. While the performance of probabilistic models on the building level are mainly driven by the choice of response distribution, multi-variable models are recommended for two reasons: First, additional resistance variables improve the detection of cases in which households were able to prevent structural losses. Second, the added variability of additional predictors provides a better representation of the uncertainties when loss estimates from multiple buildings are aggregated. This leads to the conclusion that data-driven probabilistic loss models on the building level allow for a reliable loss estimation at an unprecedented level of detail, with a consistent quantification of uncertainties on all aggregation levels. This makes the presented approach suitable for a wide range of applications, from decision support in spatial planning to impact- based early warning systems. N2 - Über die Hälfte der Weltbevölkerung lebt heute in Städten. Mit einer hohen Dichte an Menschen, Gütern und Gebäuden sind Städte nicht nur die wirtschaftlichen, politischen und kulturellen Zentren einer Gesellschaft, sondern auch besonders anfällig gegenüber Naturkatastrophen. Insbesondere Hochwasser und Überflutungen stellen in Folge von steigenden Meeresspiegeln und einer erwarteten Zunahme von Extremwettereignissen eine wachsende Bedrohung in vielen Regionen dar. Um die möglichen Folgen dieser Entwicklung zu vermeiden bzw. zu reduzieren, ist es notwendig sich der steigenden Gefahr durch geeignete Maßnahmen anzupassen. Bisher ist der Hochwasserschutz in Städten beinahe ausschließlich auf Überflutungen durch Flusshochwasser oder Sturmfluten fokussiert. Dabei werden sogenannte urbane Sturzfluten, die in den letzten Jahren vermehrt zu hohen Schäden in Städten geführt haben, nicht berücksichtigt. Bei urbanen Sturzfluten führen lokale Starkniederschläge mit hohen Regenmengen zu einer Überlastung des städtischen Abwassersystems und damit zu einer direkten, oft kleinräumigen Überflutung innerhalb eines bebauten Gebiets. Mit einer prognostizierten Zunahme von Starkniederschlägen, sowie einer baulichen Verdichtung und damit einhergehender Flächenversiegelung in vielen Städten, ist mit einer Zunahme von urbanen Sturzfluten zu rechnen. Dies verlangt die Einbindung des Risikos durch urbane Sturzfluten in bestehende Hochwasserschutzkonzepte. Bisher fehlen allerdings sowohl detaillierte Daten als auch Methoden um das Risiko durch urbane Sturzfluten und die dadurch verursachten Schäden, etwa an Wohngebäuden, zuverlässig abzuschätzen. Aus diesem Grund beschäftigt sich diese Arbeit hauptsächlich mit der Entwicklung von Verfahren und Modellen zur Abschätzung von Schäden an Privathaushalten durch urbane Sturzfluten. Dazu wurden detaillierte Daten durch Telefon- und Online-Umfragen nach urbanen Sturzflutereignissen in Deutschland und in den Niederlanden erhoben und ausgewertet. Die Erkenntnisse aus den detaillierten Analysen zu Vorsorge, Notmaßnahmen und Wiederherstellung, vor, während und nach urbanen Sturzflutereignissen, wurden genutzt um eine neue Methode zur Schätzung von Schäden an Wohngebäuden zu entwickeln. Dabei werden neben Angaben wie Dauer und Höhe der Überflutung, auch Eigenschaften von Haushalten, wie etwa deren Risikobewusstsein, in die Schätzung miteinbezogen. Nach lokaler Validierung wurde die neuentwickelte Methode beispielhaft zur Schätzung von Wohngebäudeschäden nach einem urbanen Sturzflutereignis im Großraum Houston (Texas, USA) erfolgreich angewendet. Anders als bei bisherigen Ansätzen wird der geschätzte Schaden eines Wohngebäudes nicht als einzelner Wert angegeben, sondern als Verteilung, welche die Bandbreite möglicher Schäden und deren Wahrscheinlichkeit angibt. Damit konnte die Zuverlässigkeit von Schadensschätzungen im Vergleich zu bisherigen Verfahren erheblich verbessert werden. Durch die erfolgreiche Anwendung sowohl auf der Ebene einzelner Gebäude als auch für gesamte Städte, ergibt sich ein breites Spektrum an Nutzungsmöglichkeiten, etwa als Entscheidungsunterstützung in der Stadtplanung oder für eine verbesserte Frühwarnung vor urbanen Sturzfluten. KW - Schadensmodellierung KW - Unsicherheiten KW - Starkregen KW - Privathaushalte KW - damage modeling KW - economic impacts KW - uncertainty KW - private households KW - probabilistic KW - pluvial flooding Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-429910 ER - TY - CHAP A1 - Saget, Sylvie A1 - Guyomard, Marc T1 - Goal-oriented dialog as a collaborative subordinated activity involving collective acceptance N2 - Modeling dialog as a collaborative activity consists notably in specifying the contain of the Conversational Common Ground and the kind of social mental state involved. In previous work (Saget, 2006), we claim that Collective Acceptance is the proper social attitude for modeling Conversational Common Ground in the particular case of goal-oriented dialog. We provide a formalization of Collective Acceptance, besides elements in order to integrate this attitude in a rational model of dialog are provided; and finally, a model of referential acts as being part of a collaborative activity is provided. The particular case of reference has been chosen in order to exemplify our claims. Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10420 ER - TY - JOUR A1 - Sagu Tchewonpi, Sorel A1 - Huschek, Gerd A1 - Waldbach Braga, Tess A1 - Rackiewicz, Michal A1 - Homann, Thomas A1 - Rawel, Harshadrai Manilal T1 - Design of Experiment (DoE) for Optimization of HPLC Conditions for the Simultaneous Fractionation of Seven α-Amylase/Trypsin Inhibitors from Wheat (Triticum aestivum L.) JF - Processes : open access journal N2 - Wheat alpha-amylase/trypsin inhibitors remain a subject of interest considering the latest findings showing their implication in wheat-related non-celiac sensitivity (NCWS). Understanding their functions in such a disorder is still unclear and for further study, the need for pure ATI molecules is one of the limiting problems. In this work, a simplified approach based on the successive fractionation of ATI extracts by reverse phase and ion exchange chromatography was developed. ATIs were first extracted from wheat flour using a combination of Tris buffer and chloroform/methanol methods. The separation of the extracts on a C18 column generated two main fractions of interest F1 and F2. The response surface methodology with the Doehlert design allowed optimizing the operating parameters of the strong anion exchange chromatography. Finally, the seven major wheat ATIs namely P01083, P17314, P16850, P01085, P16851, P16159, and P83207 were recovered with purity levels (according to the targeted LC-MS/MS analysis) of 98.2 ± 0.7; 98.1 ± 0.8; 97.9 ± 0.5; 95.1 ± 0.8; 98.3 ± 0.4; 96.9 ± 0.5, and 96.2 ± 0.4%, respectively. MALDI-TOF-MS analysis revealed single peaks in each of the pure fractions and the mass analysis yielded deviations of 0.4, 1.9, 0.1, 0.2, 0.2, 0.9, and 0.1% between the theoretical and the determined masses of P01083, P17314, P16850, P01085, P16851, P16159, and P83207, respectively. Overall, the study allowed establishing an efficient purification process of the most important wheat ATIs. This paves the way for further in-depth investigation of the ATIs to gain more knowledge related to their involvement in NCWS disease and to allow the absolute quantification in wheat samples. KW - wheat KW - α-amylase/trypsin inhibitors KW - fractionation KW - purification KW - reversed-phase chromatography KW - ion-exchange chromatography KW - design of experiment KW - LC–MS/MS KW - MALDI-TOF-MS Y1 - 2022 U6 - https://doi.org/10.3390/pr10020259 SN - 2227-9717 VL - 10 SP - 1 EP - 18 PB - MDPI CY - Basel, Schweiz ET - 2 ER - TY - CHAP A1 - Saléschus, Dirk T1 - On resolving long distance dependencies in Russian verbs N2 - Morphological analyses based on word syntax approaches can encounter difficulties with long distance dependencies. The reason is that in some cases an affix has to have access to the inner structure of the form with which it combines. One solution is the percolation of features from ther inner morphemes to the outer morphemes with some process of feature unification. However, the obstacle of percolation constraints or stipulated features has lead some linguists to argue in favour of other frameworks such as, e.g., realizational morphology or parallel approaches like optimality theory. This paper proposes a linguistic analysis of two long distance dependencies in the morphology of Russian verbs, namely secondary imperfectivization and deverbal nominalization.We show how these processes can be reanalysed as local dependencies. Although finitestate frameworks are not bound by such linguistically motivated considerations, we present an implementation of our analysis as proposed in [1] that does not complicate the grammar or enlarge the network unproportionally. Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-27235 ER - TY - JOUR A1 - Sarabadani, Jalal A1 - Metzler, Ralf A1 - Ala-Nissila, Tapio T1 - Driven polymer translocation into a channel: Isoflux tension propagation theory and Langevin dynamics simulations JF - Physical Review Research N2 - Isoflux tension propagation (IFTP) theory and Langevin dynamics (LD) simulations are employed to study the dynamics of channel-driven polymer translocation in which a polymer translocates into a narrow channel and the monomers in the channel experience a driving force fc. In the high driving force limit, regardless of the channel width, IFTP theory predicts τ ∝ f βc for the translocation time, where β = −1 is the force scaling exponent. Moreover, LD data show that for a very narrow channel fitting only a single file of monomers, the entropic force due to the subchain inside the channel does not play a significant role in the translocation dynamics and the force exponent β = −1 regardless of the force magnitude. As the channel width increases the number of possible spatial configurations of the subchain inside the channel becomes significant and the resulting entropic force causes the force exponent to drop below unity. Y1 - 2022 U6 - https://doi.org/10.1103/PhysRevResearch.4.033003 SN - 2643-1564 VL - 4 SP - 033003-1 EP - 033003-14 PB - American Physical Society CY - College Park, Maryland, USA ET - 3 ER - TY - JOUR A1 - Sariati, Dorsaf A1 - Hammami, Raouf A1 - Zouhal, Hassane A1 - Clark, Cain Craig Truman A1 - Nebigh, Ammar A1 - Chtara, Moktar A1 - Chortane, Sabri Gaied A1 - Hackney, Anthony C. A1 - Souissi, Nizar A1 - Granacher, Urs A1 - Ben Ounis, Omar ED - Trecroci, Athos T1 - Improvement of Physical Performance Following a 6 Week Change-of-Direction Training Program in Elite Youth Soccer Players of Different Maturity Levels JF - Frontiers in physiology N2 - Background: Change-of-direction (CoD) is a necessary physical ability of a field sport and may vary in youth players according to their maturation status. Objectives: The aim of this study is: to compare the effectiveness of a 6-week CoD training intervention on dynamic balance (CS-YBT), horizontal jump (5JT), speed (10 and 30-m linear sprint times), CoD with (15 m-CoD + B) and without (15 m-CoD) the ball, in youth male soccer players at different levels of maturity [pre- and post-peak height velocity (PHV)]. Materials and Methods: Thirty elite male youth soccer players aged 10–17 years from the Tunisian first division participated in this study. The players were divided into pre- (G1, n = 15) and post-PHV (G2, n = 15) groups. Both groups completed a similar 6-week training program with two sessions per week of four CoD exercises. All players completed the following tests before and after intervention: CS-YBT; 5 JT; 10, 30, and 15 m-CoD; and 15 m-CoD + B, and data were analyzed using ANCOVA. Results: All 30 players completed the study according to the study design and methodology. Adherence rate was 100% across all groups, and no training or test-related injuries were reported. Pre-PHV and post-PHV groups showed significant amelioration post-intervention for all dependent variables (after test > before test; p < 0.01, d = 0.09–1.51). ANOVA revealed a significant group × time interaction only for CS-YBT (F = 4.45; p < 0.04; η2 = 0.14), 5JT (F = 6.39; p < 0.02; η2 = 0.18), and 15 m-CoD (F = 7.88; p < 0.01; η2 = 0.22). CS-YBT, 5JT, and 15 m-CoD improved significantly in the post-PHV group (+ 4.56%, effect size = 1.51; + 4.51%, effect size = 1.05; and -3.08%, effect size = 0.51, respectively), more than the pre-PHV group (+ 2.77%, effect size = 0.85; + 2.91%, effect size = 0.54; and -1.56%, effect size = 0.20, respectively). Conclusion: The CoD training program improved balance, horizontal jump, and CoD without the ball in male preadolescent and adolescent soccer players, and this improvement was greater in the post-PHV players. The maturity status of the athletes should be considered when programming CoD training for soccer players. KW - youth soccer KW - peak height velocity KW - change of direction speed KW - training adaptation KW - football Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.668437 SN - 1664-042X VL - 12 SP - 1 EP - 8 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - JOUR A1 - Sariati, Dorsaf A1 - Zouhal, Hassane A1 - Hammami, Raouf A1 - Clark, Cain Craig Truman A1 - Nebigh, Ammar A1 - Chtara, Moktar A1 - Hackney, Anthony C. A1 - Souissi, Nizar A1 - Granacher, Urs A1 - Ben Ounis, Omar T1 - Association Between Mental Imagery and Change of Direction Performance in Young Elite Soccer Players of Different Maturity Status JF - Frontiers in Psychology N2 - Previous studies have not considered the potential influence of maturity status on the relationship between mental imagery and change of direction (CoD) speed in youth soccer. Accordingly, this cross-sectional study examined the association between mental imagery and CoD performance in young elite soccer players of different maturity status. Forty young male soccer players, aged 10-17 years, were assigned into two groups according to their predicted age at peak height velocity (PHV) (Pre-PHV; n = 20 and Post-PHV; n = 20). Participants were evaluated on soccer-specific tests of CoD with (CoDBall-15m) and without (CoD-15m) the ball. Participants completed the movement imagery questionnaire (MIQ) with the three- dimensional structure, internal visual imagery (IVI), external visual imagery (EVI), as well as kinesthetic imagery (KI). The Post-PHV players achieved significantly better results than Pre-PHV in EVI (ES = 1.58, large; p < 0.001), CoD-15m (ES = 2.09, very large; p < 0.001) and CoDBall-15m (ES = 1.60, large; p < 0.001). Correlations were significantly different between maturity groups, where, for the pre-PHV group, a negative very large correlation was observed between CoDBall-15m and KI (r = –0.73, p = 0.001). For the post-PHV group, large negative correlations were observed between CoD-15m and IVI (r = –0.55, p = 0.011), EVI (r = –062, p = 0.003), and KI (r = –0.52, p = 0.020). A large negative correlation of CoDBall-15m with EVI (r = –0.55, p = 0.012) and very large correlation with KI (r = –0.79, p = 0.001) were also observed. This study provides evidence of the theoretical and practical use for the CoD tasks stimulus with imagery. We recommend that sport psychology specialists, coaches, and athletes integrated imagery for CoD tasks in pre-pubertal soccer players to further improve CoD related performance. KW - mental imagery KW - football KW - maturation KW - speed KW - adolescents Y1 - 2021 U6 - https://doi.org/10.3389/fpsyg.2021.665508 SN - 1664-1078 VL - 12 SP - 1 EP - 9 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - JOUR A1 - Schachter, Allison T1 - Barry Trachtenberg, The Holocaust & the Exile of Yiddish: A History of the Algemeyne Entsiklopedye (New Brunswick, NJ: Rutgers University Press, 2022), 336 pp., $ 37.50 JF - PaRDeS : Journal of the Association for Jewish Studies in Germany JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien e.V. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-585836 SN - 978-3-86956-552-1 SN - 1614-6492 SN - 1862-7684 IS - 28 SP - 121 EP - 125 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Schaefer, Laura A1 - Dech, Silas A1 - Aehle, Markus A1 - Bittmann, Frank T1 - Disgusting odours affect the characteristics of the adaptive force in contrast to neutral and pleasant odours JF - Scientific Reports N2 - The olfactomotor system is especially investigated by examining the sniffing in reaction to olfactory stimuli. The motor output of respiratory-independent muscles was seldomly considered regarding possible influences of smells. The Adaptive Force (AF) characterizes the capability of the neuromuscular system to adapt to external forces in a holding manner and was suggested to be more vulnerable to possible interfering stimuli due to the underlying complex control processes. The aim of this pilot study was to measure the effects of olfactory inputs on the AF of the hip and elbow flexors, respectively. The AF of 10 subjects was examined manually by experienced testers while smelling at sniffing sticks with neutral, pleasant or disgusting odours. The reaction force and the limb position were recorded by a handheld device. The results show, inter alia, a significantly lower maximal isometric AF and a significantly higher AF at the onset of oscillations by perceiving disgusting odours compared to pleasant or neutral odours (p < 0.001). The adaptive holding capacity seems to reflect the functionality of the neuromuscular control, which can be impaired by disgusting olfactory inputs. An undisturbed functioning neuromuscular system appears to be characterized by a proper length tension control and by an earlier onset of mutual oscillations during an external force increase. This highlights the strong connection of olfaction and motor control also regarding respiratory-independent muscles. Y1 - 2021 U6 - https://doi.org/10.1038/s41598-021-95759-0 SN - 2045-2322 VL - 11 SP - 1 EP - 16 PB - Springer Nature CY - London ER - TY - THES A1 - Schauer, Nicolas T1 - Quantitative trait loci (QTL) for metabolite accumulation and metabolic regulation : metabolite profiling of interspecific crosses of tomato T1 - Metabolomische Analyse von interspezifischen Tomaten N2 - The advent of large-scale and high-throughput technologies has recently caused a shift in focus in contemporary biology from decades of reductionism towards a more systemic view. Alongside the availability of genome sequences the exploration of organisms utilizing such approach should give rise to a more comprehensive understanding of complex systems. Domestication and intensive breeding of crop plants has led to a parallel narrowing of their genetic basis. The potential to improve crops by conventional breeding using elite cultivars is therefore rather limited and molecular technologies, such as marker assisted selection (MAS) are currently being exploited to re-introduce allelic variance from wild species. Molecular breeding strategies have mostly focused on the introduction of yield or resistance related traits to date. However given that medical research has highlighted the importance of crop compositional quality in the human diet this research field is rapidly becoming more important. Chemical composition of biological tissues can be efficiently assessed by metabolite profiling techniques, which allow the multivariate detection of metabolites of a given biological sample. Here, a GC/MS metabolite profiling approach has been applied to investigate natural variation of tomatoes with respect to the chemical composition of their fruits. The establishment of a mass spectral and retention index (MSRI) library was a prerequisite for this work in order to establish a framework for the identification of metabolites from a complex mixture. As mass spectral and retention index information is highly important for the metabolomics community this library was made publicly available. Metabolite profiling of tomato wild species revealed large differences in the chemical composition, especially of amino and organic acids, as well as on the sugar composition and secondary metabolites. Intriguingly, the analysis of a set of S. pennellii introgression lines (IL) identified 889 quantitative trait loci of compositional quality and 326 yield-associated traits. These traits are characterized by increases/decreases not only of single metabolites but also of entire metabolic pathways, thus highlighting the potential of this approach in uncovering novel aspects of metabolic regulation. Finally the biosynthetic pathway of the phenylalanine-derived fruit volatiles phenylethanol and phenylacetaldehyde was elucidated via a combination of metabolic profiling of natural variation, stable isotope tracer experiments and reverse genetic experimentation. N2 - Die Einführung von Hochdurchsatzmethoden zur Analyse von biologischen Systemen, sowie die umfangreiche Sequenzierung von Genomen haben zu einer Verlagerung der Forschung „im Detail“ zu einer ganzheitlicheren Betrachtungsweise auf Systemebene geführt. Aus einer jahrhundertlangen, intensiven Züchtung und Selektion von Nutzpflanzen resultierte gleichzeitig eine Abnahme der genetischen Varianz. Daraus resultierend sind Nutzpflanzen anfälliger gegenüber Stressfaktoren, wie Pathogenen, hohen Salzkonzentrationen oder Trockenheit, als ihre Wildarten. Das Potential konventioneller Züchtung scheint somit heute an seine Grenzen gekommen zu sein. Daher versucht man mittels moderner Molekulartechnik, wie zum Beispiel Marker-gestützte Selektion, Gene oder ganze Genombereiche von Wildarten mit hoher genetischer Variation in Nutzpflanzen einzukreuzen, vornehmlich mit dem Ziel einer Ertrags- bzw. Resistenzsteigerung. Neueste medizinische Studien belegen, dass die Ernährung eine wesentliche Rolle für die menschliche Gesundheit spielt. Besonders wichtig sind hierbei die gesundheitsfördernden Substanzen in pflanzlichen Nahrungsmitteln. Aus diesem Grund kommt der Erforschung der biochemischen Zusammensetzung von biologischen Proben eine immer größere Bedeutung zu. Diese Untersuchung kann elegant durch Metabolitenprofile, welche die multivariate Analyse komplexer biologischer Proben erlauben, durchgeführt werden. In dieser Arbeit wurde zur Untersuchung der biochemischen Zusammensetzung von Tomatenwildarten und interspezifischen S. pennellii Tomatenintrogressionslinien (IL) eine GC/MS basierte Metabolitenanalyseplattform verwendet. Hierzu war es zunächst notwendig eine Massenspektrenbibliothek, zur Annotierung von Massenspektren und Retentionsindices von, in pflanzlichen Proben vorkommenden, Metaboliten anzulegen. Die Analyse der Tomatenwildarten ergab große Unterschiede gegenüber der Kulturtomate im Hinblick auf den Gehalt an Amino- und organischen Säuren, sowie der Zuckerzusammensetzung und den Gehalt an Sekundärmetaboliten. Die darauf folgende Analyse der ILs, von den jede ein genau definiertes genomisches Segment von S. pennellii beinhaltet, bestätigte diese enorme Variation mit 889 metabolischen und 326 ertragsassozierten-Veränderungen in den ILs. Die metabolischen Veränderungen zeichneten sich durch abnehmende bzw. steigende Gehalte von einzelnen Metaboliten, aber auch durch eine koordinierte Änderung aus. In dieser Arbeit wurde weiterhin der Biosyntheseweg der Volatilenstoffe Phenylethanol und Phenylacetaldehyd mit Hilfe einer IL untersucht. Hierbei konnten durch stabile Isotopenmarkierung und eines „reverse genetics“-Ansatzes Gene bzw. Enzyme identifiziert werden, die für die Dekarboxylierung des Eduktes Phenylalanin verantwortlich sind. Diese Arbeit beschreibt erstmals die umfassende Analyse von biochemischen Komponenten auf Genombasis in Tomatenintrogressionslinien und zeigt damit ein Werkzeug auf zur Identifizierung von qualitativen biochemischen Merkmalen in der modernen molekularen Züchtung. KW - Tomate KW - Metabolit KW - GC-MS KW - Introgression KW - Frucht KW - Metabolome KW - Züchtung KW - metabolic genomics KW - Tomato KW - metabolite profiling KW - metabolome KW - breeding KW - crops KW - fruit KW - metabolite breeding KW - metabolic genomics Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7643 ER - TY - JOUR A1 - Scheck-Wenderoth, Magdalena A1 - Cacace, Mauro A1 - Maystrenko, Yuriy Petrovich A1 - Cherubini, Yvonne A1 - Noack, Vera A1 - Kaiser, Bjoern Onno A1 - Sippel, Judith A1 - Bjoern, Lewerenz T1 - Models of heat transport in the Central European Basin System: Effective mechanisms at different scales JF - Marine and petroleum geology N2 - Understanding heat transport in sedimentary basins requires an assessment of the regional 3D heat distribution and of the main physical mechanisms responsible for the transport of heat. We review results from different 3D numerical simulations of heat transport based on 3D basin models of the Central European Basin System (CEBS). Therefore we compare differently detailed 3D structural models of the area, previously published individually, to assess the influence of (1) different configurations of the deeper lithosphere, (2) the mechanism of heat transport considered and (3) large faults dissecting the sedimentary succession on the resulting thermal field and groundwater flow. Based on this comparison we propose a modelling strategy linking the regional and lithosphere-scale to the sub-basin and basin-fill scale and appropriately considering the effective heat transport processes. We find that conduction as the dominant mechanism of heat transport in sedimentary basins is controlled by the distribution of thermal conductivities, compositional and thickness variations of both the conductive and radiogenic crystalline crust as well as the insulating sediments and by variations in the depth to the thermal lithosphere-asthenosphere boundary. Variations of these factors cause thermal anomalies of specific wavelength and must be accounted for in regional thermal studies. In addition advective heat transport also exerts control on the thermal field on the regional scale. In contrast, convective heat transport and heat transport along faults is only locally important and needs to be considered for exploration on the reservoir scale. The general applicability of the proposed workflow makes it of interest for a broad range of application in geosciences including oil and gas exploration, geothermal utilization or carbon capture and sequestration issues. (C) 2014 Elsevier Ltd. All rights reserved. KW - 3D thermal model KW - Geothermal field KW - Sedimentary basin KW - Heat transport by conduction KW - Advection and convection KW - Central European Basin System Y1 - 2014 U6 - https://doi.org/10.1016/j.marpetgeo.2014.03.009 SN - 0264-8172 SN - 1873-4073 VL - 55 SP - 315 EP - 331 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - What does stunting tell us? JF - Human biology and public health N2 - Stunting is commonly linked with undernutrition. Yet, already after World War I, German pediatricians questioned this link and stated that no association exists between nutrition and height. Recent analyses within different populations of Low- and middle-income countries with high rates of stunted children failed to support the assumption that stunted children have a low BMI and skinfold sickness as signs of severe caloric deficiency. So, stunting is not a synonym of malnutrition. Parental education level has a positive influence on body height in stunted populations, e.g., in India and in Indonesia. Socially disadvantaged children tend to be shorter and lighter than children from affluent families. Humans are social mammals; they regulate growth similar to other social mammals. Also in humans, body height is strongly associated with the position within the social hierarchy, reflecting the personal and group-specific social, economic, political, and emotional environment. These non-nutritional impact factors on growth are summarized by the concept of SEPE (Social-Economic-Political-Emotional) factors. SEPE reflects on prestige, dominance-subordination, social identity, and ego motivation of individuals and social groups. KW - SEPE Factors KW - physical fitness KW - height in history KW - malnutrition Y1 - 2023 U6 - https://doi.org/10.52905/hbph2022.3.36 SN - 2748-9957 VL - 2022 IS - 3 SP - 1 EP - 15 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - Stunting does not impair physical fitness in Indonesian school children JF - Human biology and public health N2 - Background: Physical fitness is decreased in malnourished children and adults. Poor appearance and muscular flaccidity are among the first signs of malnutrition. Malnutrition is often associated with stunting. Objectives: We test the hypotheses that stunted children of low social strata are physically less fit than children of high social strata. Sample: We investigated 354 school girls and 369 school boys aged 5.83 to 13.83 (mean 9.54) years from three different social strata in Kupang (West-Timor, Indonesia) in 2020. Methods: We measured height, weight, and elbow breadth, calculated standard deviation (SDS) of height and weight according to CDC references, and the Frame index as an indicator of long-term physical fitness, and we tested physical fitness in standing long jump and hand grip strength. Results: Children of low social strata are physically fittest. They jump longer distances, and they have higher values in the Frame index. No association exists between height SDS and physical fitness, neither in respect to standing long jump, nor to hand grip strength. Conclusion: Stunting does not impair physical fitness in Indonesian school children. Our results support the concept that SEPE (social-economic-political-emotional) factors are involved in the regulation of human growth. KW - stunting KW - standing long jump KW - handgrip strength KW - SEPE KW - frame index Y1 - 2021 U6 - https://doi.org/10.52905/hbph.v2.19 SN - 2748-9957 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Scheffler, Christiane A1 - Nguyen, Thi Hong A1 - Hermanussen, Michael T1 - Vietnamese migrants are as tall as they want to be JF - Human biology and public health N2 - Background: Members of the same social group tent to have the same body height. Migrants tend to adjust in height to their host communities. Objectives: Social-Economic-Political-Emotional (SEPE) factors influence growth. We hypothesized that Vietnamese young adult migrants in Germany (1) are taller than their parents, (2) are as tall as their German peers, and (3) are as tall as predicted by height expectation at age 13 years. Sample: The study was conducted in 30 male and 54 female Vietnamese migrants (mean age 26.23 years. SD=4.96) in Germany in 2020. Methods: Information on age, sex, body height, school and education, job, height and ethnicity of best friend, migration history and cultural identification, parental height and education, and recalled information on their personal height expectations at age 13 years were obtained by questionnaire. The data were analyzed by St. Nicolas House Analysis (SNHA) and multiple regression. Results: Vietnamese young adults are taller than their parents (females 3.85cm, males 7.44cm), but do not fully attain height of their German peers. The body height is positively associated with the height of best friend (p < 0.001), the height expectation at age 13 year (p < 0.001), and father’s height (p=0.001). Conclusion: Body height of Vietnamese migrants in Germany reflects competitive growth and strategic growth adjustments. The magnitude of this intergenerational trend supports the concept that human growth depends on SEPE factors. KW - body height KW - regulation of growth KW - migrants KW - Social-Economic-Political-Emotional (SEPE) factors Y1 - 2021 U6 - https://doi.org/10.52905/hbph.v2.12 SN - 2748-9957 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Scheffler, Christiane A1 - Rogol, Alan D. A1 - Iancu, Mirela A1 - Hanc, Tomasz A1 - Moelyo, Annang Giri A1 - Suchomlinov, Andrej A1 - Lebedeva, Lidia A1 - Limony, Yehuda A1 - Musalek, Martin A1 - Veldre, Gudrun A1 - Godina, Elena Z. A1 - Kirchengast, Sylvia A1 - Mumm, Rebekka A1 - Groth, Detlef A1 - Tutkuviene, Janina A1 - Böker, Sonja A1 - Ozer, Basak Koca A1 - Navazo, Barbara A1 - Spake, Laure A1 - Koziel, Slawomir A1 - Hermanussen, Michael T1 - Growth during times of fear and emotional stress BT - Proceedings of the 28th Aschauer Soiree, held at Potsdam, Germany, and online, November 14th 2020 JF - Human biology and public health N2 - Twenty-one scientists met for this year’s virtual conference on Auxology held at the University Potsdam, Germany, to discuss child and adolescent growth during times of fear and emotional stress. Growth within the broad range of normal for age and sex is considered a sign of good general health whereas fear and emotional stress can lead to growth faltering. Stunting is a sign of social disadvantage and poor parental education. Adverse childhood experiences affect child development, particularly in families with low parental education and low socioeconomic status. Negative effects were also shown in Indian children exposed prenatally and in early postnatal life to the cyclone Aila in 2009. Distrust, fears and fake news regarding the current Corona pandemic received particular attention though the effects generally appeared weak. Mean birth weight was higher; rates of low, very and extremely low birth weight were lower. Other topics discussed by the participants, were the influences of economic crises on birth weight, the measurement of self-confidence and its impact on growth, the associations between obesity, peer relationship, and behavior among Turkish adolescents, height trends in Indonesia, physiological neonatal weight loss, methods for assessing biological maturation in sportsmen, and a new method for skeletal age determination. The participants also discussed the association between acute myocardial infarction and somatotype in Estonia, rural-urban growth differences in Mongolian children, socio-environmental conditions and sexual dimorphism, biological mortality bias, and new statistical techniques for describing inhomogeneity in the association of bivariate variables, and for detecting and visualizing extensive interactions among variables. KW - stunting KW - birth weight KW - fear KW - emotional stress KW - economy KW - SEPE Y1 - 2021 U6 - https://doi.org/10.52905/hbph.v2.15 SN - 2748-9957 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Schemenz, Victoria T1 - Correlations between osteocyte lacuno-canalicular network and material characteristics in bone adaptation and regeneration T1 - Korrelationen zwischen dem lakuno-kanalikulären Netzwerk der Osteozyten und Materialeigenschaften bei der Knochenanpassung und -regeneration N2 - The complex hierarchical structure of bone undergoes a lifelong remodeling process, where it adapts to mechanical needs. Hereby, bone resorption by osteoclasts and bone formation by osteoblasts have to be balanced to sustain a healthy and stable organ. Osteocytes orchestrate this interplay by sensing mechanical strains and translating them into biochemical signals. The osteocytes are located in lacunae and are connected to one another and other bone cells via cell processes through small channels, the canaliculi. Lacunae and canaliculi form a network (LCN) of extracellular spaces that is able to transport ions and enables cell-to-cell communication. Osteocytes might also contribute to mineral homeostasis by direct interactions with the surrounding matrix. If the LCN is acting as a transport system, this should be reflected in the mineralization pattern. The central hypothesis of this thesis is that osteocytes are actively changing their material environment. Characterization methods of material science are used to achieve the aim of detecting traces of this interaction between osteocytes and the extracellular matrix. First, healthy murine bones were characterized. The properties analyzed were then compared with three murine model systems: 1) a loading model, where a bone of the mouse was loaded during its life time; 2) a healing model, where a bone of the mouse was cut to induce a healing response; and 3) a disease model, where the Fbn1 gene is dysfunctional causing defects in the formation of the extracellular tissue. The measurement strategy included routines that make it possible to analyze the organization of the LCN and the material components (i.e., the organic collagen matrix and the mineral particles) in the same bone volumes and compare the spatial distribution of different data sets. The three-dimensional network architecture of the LCN is visualized by confocal laser scanning microscopy (CLSM) after rhodamine staining and is then subsequently quantified. The calcium content is determined via quantitative backscattered electron imaging (qBEI), while small- and wide-angle X-ray scattering (SAXS and WAXS) are employed to determine the thickness and length of local mineral particles. First, tibiae cortices of healthy mice were characterized to investigate how changes in LCN architecture can be attributed to interactions of osteocytes with the surrounding bone matrix. The tibial mid-shaft cross-sections showed two main regions, consisting of a band with unordered LCN surrounded by a region with ordered LCN. The unordered region is a remnant of early bone formation and exhibited short and thin mineral particles. The surrounding, more aligned bone showed ordered and dense LCN as well as thicker and longer mineral particles. The calcium content was unchanged between the two regions. In the mouse loading model, the left tibia underwent two weeks of mechanical stimulation, which results in increased bone formation and decreased resorption in skeletally mature mice. Here the specific research question addressed was how do bone material characteristics change at (re)modeling sites? The new bone formed in response to mechanical stimulation showed similar properties in terms of the mineral particles, like the ordered calcium region but lower calcium content compared to the right, non-loaded control bone of the same mice. There was a clear, recognizable border between mature and newly formed bone. Nevertheless, some canaliculi went through this border connecting the LCN of mature and newly formed bone. Additionally, the question should be answered whether the LCN topology and the bone matrix material properties adapt to loading. Although, mechanically stimulated bones did not show differences in calcium content compared to controls, different correlations were found between the local LCN density and the local Ca content depending on whether the bone was loaded or not. These results suggest that the LCN may serve as a mineral reservoir. For the healing model, the femurs of mice underwent an osteotomy, stabilized with an external fixator and were allowed to heal for 21 days. Thus, the spatial variations in the LCN topology with mineral properties within different tissue types and their interfaces, namely calcified cartilage, bony callus and cortex, could be simultaneously visualized and compared in this model. All tissue types showed structural differences across multiple length scales. Calcium content increased and became more homogeneous from calcified cartilage to bony callus to lamellar cortical bone. The degree of LCN organization increased as well, while the lacunae became smaller, as did the lacunar density between these different tissue types that make up the callus. In the calcified cartilage, the mineral particles were short and thin. The newly formed callus exhibited thicker mineral particles, which still had a low degree of orientation. While most of the callus had a woven-like structure, it also served as a scaffold for more lamellar tissue at the edges. The lamelar bone callus showed thinner mineral particles, but a higher degree of alignment in both, mineral particles and the LCN. The cortex showed the highest values for mineral length, thickness and degree of orientation. At the same time, the lacunae number density was 34% lower and the lacunar volume 40% smaller compared to bony callus. The transition zone between cortical and callus regions showed a continuous convergence of bone mineral properties and lacunae shape. Although only a few canaliculi connected callus and the cortical region, this indicates that communication between osteocytes of both tissues should be possible. The presented correlations between LCN architecture and mineral properties across tissue types may suggest that osteocytes have an active role in mineralization processes of healing. A mouse model for the disease marfan syndrome, which includes a genetic defect in the fibrillin-1 gene, was investigated. In humans, Marfan syndrome is characterized by a range of clinical symptoms such as long bone overgrowth, loose joints, reduced bone mineral density, compromised bone microarchitecture, and increased fracture rates. Thus, fibrillin-1 seems to play a role in the skeletal homeostasis. Therefore, the present work studied how marfan syndrome alters LCN architecture and the surrounding bone matrix. The mice with marfan syndrome showed longer tibiae than their healthy littermates from an age of seven weeks onwards. In contrast, the cortical development appeared retarded, which was observed across all measured characteristics, i. e. lower endocortical bone formation, looser and less organized lacuno-canalicular network, less collagen orientation, thinner and shorter mineral particles. In each of the three model systems, this study found that changes in the LCN architecture spatially correlated with bone matrix material parameters. While not knowing the exact mechanism, these results provide indications that osteocytes can actively manipulate a mineral reservoir located around the canaliculi to make a quickly accessible contribution to mineral homeostasis. However, this interaction is most likely not one-sided, but could be understood as an interplay between osteocytes and extra-cellular matrix, since the bone matrix contains biochemical signaling molecules (e.g. non-collagenous proteins) that can change osteocyte behavior. Bone (re)modeling can therefore not only be understood as a method for removing defects or adapting to external mechanical stimuli, but also for increasing the efficiency of possible osteocyte-mineral interactions during bone homeostasis. With these findings, it seems reasonable to consider osteocytes as a target for drug development related to bone diseases that cause changes in bone composition and mechanical properties. It will most likely require the combined effort of materials scientists, cell biologists, and molecular biologists to gain a deeper understanding of how bone cells respond to their material environment. N2 - Knochen haben eine komplexe hierarchische Struktur, die einen lebenslangen Umbauprozess durchläuft, bei dem der Knochen sich seinen mechanischen Anforderungen anpasst. Um ein gesundes und stabiles Organ zu erhalten müssen Knochenresorption (durch Osteoklasten) und Knochenbildung (durch Osteoblasten) ausgewogen sein. Osteozyten lenken dieses Wechselspiel, indem sie mechanische Belastungen wahrnehmen und sie in biochemische Signale übersetzen. Die Osteozyten sitzen in Lakunen und sind durch Kanälchen untereinander und mit anderen Knochenzellen über ein Netzwerk (LCN) verbunden, das in der Lage ist, Ionen zu transportieren und eine Kommunikation von Zelle zu Zelle zu ermöglichen. Außerdem vermutet man, dass Osteozyten auch durch direkte Wechselwirkungen mit der umgebenden Matrix zur Mineralhomöostase beitragen könnten. Im Mittelpunkt dieser Arbeit steht die Frage, ob Osteozyten ihre materielle Umgebung aktiv verändern können. Um Spuren dieser Wechselwirkung zwischen Osteozyten und der extrazellulären Matrix nachzuweisen, werden materialwissenschaftliche Charakterisierungsmethoden eingesetzt. Zunächst wurden gesunde Mäuseknochen charakterisiert. Die erworbenen Ergebnisse wurden dann mit drei murinen Modellsystemen verglichen: 1) einem Belastungsmodell; 2) ein Heilungsmodell und 3) ein Krankheitsmodell, bei dem das Fbn1-Gen dysfunktional ist und Defekte in der Bildung des extrazellulären Gewebes verursacht werden. Die Messstrategie umfasste Routinen, die es ermöglichen, die Organisation des LCN und der Materialkomponenten (d.h. die organische Kollagenmatrix und die mineralischen Partikel) in denselben Knochenvolumina zu analysieren und die räumliche Verteilung der verschiedenen Datensätze zu vergleichen. Die dreidimensionale Netzwerkarchitektur des LCN wird durch konfokale Laser-Scanning-Mikroskopie nach Rhodamin-Färbung gemessen und anschließend quantifiziert. Der Kalziumgehalt wird mittels quantitativer Rückstreuelektronenbildgebung bestimmt, während Klein- und Weitwinkel-Röntgenstreuung verwendet werden, um die Dicke und Länge der Mineralpartikel zu bestimmen. Zunächst wurden Querschnitte der Unterschenkel von gesunden Mäusen charakterisiert, um zu untersuchen, ob Veränderungen in der LCN-Architektur auf Wechselwirkungen von Osteozyten mit der umgebenden Knochenmatrix zurückgeführt werden können. Die Kortizes zeigten zwei Hauptregionen, ein Band mit ungeordneter LCN-Architektur, umgeben von einer Region mit geordneter LCN. Die ungeordnete Region ist ein Überbleibsel der frühen Knochenbildung und wies kurze und dünne Mineralpartikel auf. Der umgebende, stärker ausgerichtete Knochen zeigte ein geordnetes und dichtes LCN, sowie dickere und längere Mineralpartikel. Der Kalziumgehalt blieb bei beiden Regionen unverändert. Im Mausbelastungsmodell wurde das linke Schienbein zwei Wochen lang mechanisch stimuliert, was zu einer erhöhten Knochenbildung führt. Hier sollte die Forschungsfrage beantwortet werden, wie sich Knochenmaterialeigenschaften an (Re-)Modellierungsstellen aufgrund von Belastung ändern. Der, als Reaktion auf die mechanische Stimulation, gebildete neue Knochen zeigte ähnliche Eigenschaften in Bezug auf die Mineralpartikel, wie die geordnete Kortexregion. Es gab eine klar erkennbare Grenze zwischen reifem und neu gebildetem Knochen. Trotzdem gingen einige Kanälchen durch diese Grenze, die die LCN aus reifem und neu gebildetem Knochen verband. Für das Heilungsmodell wurden die Oberschenkel von Mäusen einer Osteotomie unterzogen (einer Operation, bei der durch einen Schnitt in der Diaphyse ein Bruch erzeugt wird). Danach konnte die Fraktur 21 Tage heilen. Dadurch konnten in diesem Modell gleichzeitig verkalkter Knorpel, knöcherner Kallus und Kortex untersucht werden. Dafür wurde die räumliche Verteilung der LCN-Topologie sowie die Mineraleigenschaften der verschiedenen Gewebetypen und ihrer Grenzflächen visualisiert und verglichen. Alle Gewebetypen zeigten strukturelle Unterschiede über mehrere Längenskalen hinweg. Der Kalziumgehalt nahm von kalzifiziertem Knorpel zu knöchernem Kallus zu lamellarem kortikalem Knochen zu und wurde homogener. Der Grad der LCN-Organisation nahm ebenfalls zu, während die Lakunen vom Kallus zum Kortexgewebe kleiner wurden, ebenso wie die Lakunendichte. Im verkalkten Knorpel waren die Mineralpartikel kurz und dünn. Der größte Teil des Kallus wies eine Geflechtsknochenstruktur auf und diente als Gerüst für lamellares Gewebe, das dünnere Mineralpartikel, aber einen höheren Grad an Ausrichtung sowohl in den Mineralpartikeln als auch im LCN aufwies. Der Kortex zeigte die höchsten Werte für Minerallänge, Dicke und Orientierungsgrad. Obwohl nur wenige Kanälchen den Kallus und kortikale Regionen verbinden, weist dies darauf hin, dass eine Kommunikation zwischen Osteozyten beider Gewebe möglich sein sollte. Es wurde auch ein Mausmodell für das Marfan-Syndrom untersucht, das einen Gendefekt im Fibrillin-1-Gen beinhaltet. Beim Menschen ist das Marfan-Syndrom durch eine Reihe klinischer Symptome gekennzeichnet, wie z. B. übermäßiges Wachstum der Gliedmaßen, überstreckbare Gelenke, verringerte Knochenmineraldichte, beeinträchtigte Knochenmikroarchitektur und erhöhte Frakturraten. Somit scheint Fibrillin-1 eine Rolle in der Skeletthomöostase zu spielen. Deswegen untersuchte die vorliegende Arbeit, ob und wie das Marfan-Syndrom die LCN-Architektur und die umgebende Knochenmatrix verändert. Die Mäuse mit Marfan-Syndrom zeigten bereits ab einem Alter von sieben Wochen längere Schienbeine als ihre gesunden Wurfgeschwister. Im Gegensatz dazu erschien die kortikale Entwicklung verzögert, was über alle gemessenen Merkmale hinweg beobachtet wurde, d.h. niedrigere endokortikale Knochenbildung, lockereres und weniger organisiertes LCN, geringerer Grad an Kollagenorientierung sowie ein Trend zu dünneren und kürzeren Mineralpartikel. In jedem der drei Modellsysteme fand diese Studie, dass Änderungen in der LCN-Architektur räumlich mit Parametern des Knochenmatrixmaterials korrelierten. Obwohl der genaue Mechanismus nicht bekannt ist, liefern diese Ergebnisse Hinweise darauf, dass Osteozyten ein Mineralreservoir aktiv manipulieren können. Dieses Reservoir befindet sich um die Kanälchen herum und dieser Prozess würde es ermöglichen, einen schnell zugänglichen Beitrag zur Mineralhomöostase zu leisten. Diese Interaktion ist jedoch höchstwahrscheinlich nicht einseitig, sondern könnte als Wechselspiel zwischen Osteozyten und extrazellulärer Matrix verstanden werden, da die Knochenmatrix biochemische Signalmoleküle enthält, die das Verhalten von Osteozyten verändern können. Knochen(re)modellierung kann daher nicht nur als Methode zur Defektbeseitigung oder Anpassung an äußere mechanische Reize verstanden werden, sondern auch zur Effizienzsteigerung möglicher Osteozyten-Mineral-Interaktionen während der Knochenhomöostase. Angesichts dieser Ergebnisse erscheint es sinnvoll, Osteozyten als Ziel für die Arzneimittelentwicklung im Zusammenhang mit Knochenerkrankungen in Betracht zu ziehen, die Veränderungen der Knochenzusammensetzung und deren mechanischen Eigenschaften verursachen. KW - bone KW - lacunae KW - mineralization KW - SAXS KW - lacuno-canalicular network KW - µCT KW - CLSM KW - konfokales Laser-Scanning-Mikroskop KW - Kleinwinkelröntgenstreuung KW - Knochen KW - Lakunen KW - lakuno-kanaliculäres Netzwerk KW - Mineralisierung KW - µCT Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-559593 ER - TY - THES A1 - Schifferle, Lukas T1 - Optical properties of (Mg,Fe)O at high pressure T1 - Optische Eigenschaften von (Mg,Fe)O unter Hochdruck N2 - Large parts of the Earth’s interior are inaccessible to direct observation, yet global geodynamic processes are governed by the physical material properties under extreme pressure and temperature conditions. It is therefore essential to investigate the deep Earth’s physical properties through in-situ laboratory experiments. With this goal in mind, the optical properties of mantle minerals at high pressure offer a unique way to determine a variety of physical properties, in a straight-forward, reproducible, and time-effective manner, thus providing valuable insights into the physical processes of the deep Earth. This thesis focusses on the system Mg-Fe-O, specifically on the optical properties of periclase (MgO) and its iron-bearing variant ferropericlase ((Mg,Fe)O), forming a major planetary building block. The primary objective is to establish links between physical material properties and optical properties. In particular the spin transition in ferropericlase, the second-most abundant phase of the lower mantle, is known to change the physical material properties. Although the spin transition region likely extends down to the core-mantle boundary, the ef-fects of the mixed-spin state, where both high- and low-spin state are present, remains poorly constrained. In the studies presented herein, we show how optical properties are linked to physical properties such as electrical conductivity, radiative thermal conductivity and viscosity. We also show how the optical properties reveal changes in the chemical bonding. Furthermore, we unveil how the chemical bonding, the optical and other physical properties are affected by the iron spin transition. We find opposing trends in the pres-sure dependence of the refractive index of MgO and (Mg,Fe)O. From 1 atm to ~140 GPa, the refractive index of MgO decreases by ~2.4% from 1.737 to 1.696 (±0.017). In contrast, the refractive index of (Mg0.87Fe0.13)O (Fp13) and (Mg0.76Fe0.24)O (Fp24) ferropericlase increases with pressure, likely because Fe Fe interactions between adjacent iron sites hinder a strong decrease of polarizability, as it is observed with increasing density in the case of pure MgO. An analysis of the index dispersion in MgO (decreasing by ~23% from 1 atm to ~103 GPa) reflects a widening of the band gap from ~7.4 eV at 1 atm to ~8.5 (±0.6) eV at ~103 GPa. The index dispersion (between 550 and 870 nm) of Fp13 reveals a decrease by a factor of ~3 over the spin transition range (~44–100 GPa). We show that the electrical band gap of ferropericlase significantly widens up to ~4.7 eV in the mixed spin region, equivalent to an increase by a factor of ~1.7. We propose that this is due to a lower electron mobility between adjacent Fe2+ sites of opposite spin, explaining the previously observed low electrical conductivity in the mixed spin region. From the study of absorbance spectra in Fp13, we show an increasing covalency of the Fe-O bond with pressure for high-spin ferropericlase, whereas in the low-spin state a trend to a more ionic nature of the Fe-O bond is observed, indicating a bond weakening effect of the spin transition. We found that the spin transition is ultimately caused by both an increase of the ligand field-splitting energy and a decreasing spin-pairing energy of high-spin Fe2+. N2 - Geodynamische Prozesse werden von den physikalischen Materialeigenschaften unter den extremen Druck- und Temperaturbedingungen des Erdinneren gesteuert, gerade diese Areale sind aber faktisch nicht für direkte Beobachtungen zugänglich. Umso wichtiger ist es, die physikalischen Eigenschaften unter Bedingungen des Erdinneren zu untersuchen. Mit diesem Ziel vor Augen erlaubt das Studium der optischen Eigenschaften von Mineralen des Erdmantels, eine große Bandbreite an physikalischen Materialeigenschaften, in einer einfachen, reproduzierbaren und effizienten Art und Weise zu bestimmen. Dadurch bieten sich wichtige Einblicke in die physikalischen Prozessen des Erdinneren. Die vorliegende Arbeit konzentriert sich auf das System Mg-Fe-O, im Speziellen auf Periklas (MgO) und seine Eisen-haltige Variante Ferroperiklas ((Mg,Fe)O), ein wichtiger Baustein planetarer Körper. Das Hauptziel der Arbeit besteht darin Verbindungen zwischen optischen Eigenschaften und physikalischen Materialeigenschaften zu finden. Gerade der Spin-Übergang in Ferroperiklas, der zweithäufigsten Phase des unteren Erdmantels, ist dabei von Bedeutung, da damit Veränderungen in den physikalischen Materialeigenschaften einhergehen. Obwohl sich der Spinübergangsbereich vermutlich bis zur Kern-Mantel-Grenze erstreckt, sind die Auswirkungen des gemischten Spin-Zustandes, bei dem sowohl Hoch- als auch Tief-Spin präsent sind, nur unzureichend untersucht. Die hier vorgestellten Studien zeigen, wie optische Eigenschaften mit anderen wichtigen physikalischen Eigenschaften wie elektrischer und thermischer Leitfähigkeit, Viskosität oder auch mit der chemischen Bindung verbunden sind. Daraus lässt sich auch ableiten wie der Spin-Übergang in Ferroperiklas diese Eigenschaften beeinflusst. Von Raumbedingungen bis zu ~140 GPa sinkt der Brechungsindex von MgO um ~2.4 % von 1.737 auf 1.696 (±0.017). Im Gegensatz dazu steigt der Brechungsindex von (Mg0.87Fe0.13)O (Fp13) und (Mg0.76Fe0.24)O (Fp24) Ferroperiklas mit dem Druck an. Dies ist auf Fe-Fe Wechselwirkungen zwischen benachbarten Eisenpositionen zurückzuführen, die eine starke Verringerung der Polarisierbarkeit, wie im Falle von reinem MgO mit zunehmender Dichte, behindern. Eine Analyse der Dispersion des Brechungsindexes von MgO (Abnahme um ~23 % von 1 Atm zu ~103 GPa) offenbart eine Verbreiterung der Bandlücke von ~7.4 eV bei 1 Atm zu ~8.5 (±0.6) eV bei ~103 GPa. Die Messung der Dispersion (zwischen 550 und 870 nm) in Fp13 zeigt eine starke Abnahme über den Bereich des Spin-Überganges (~44–100 GPa) bis zu einem Faktor von ~3. Die Bandlücke nimmt in der Region des gemischten Spin-Zustandes signifikant auf bis zu ~4.7 eV zu (entspricht einer Zunahme um den Faktor ~1.7). Dies deutet auf eine Verringerung der Elektronen-Mobilität zwischen benachbarten Fe2+-Positionen mit unterschiedlichem Spin-Zustand hin, was die bereits in früheren Arbeiten beobachtete Abnahme der elektrischen Leitfähigkeit im Bereich des gemischten Spin-Zustandes erklärt. Absorptionsspektren an Fp13 zeigen eine Druck-bedingte Zunahme der Kovalenz der Fe-O Bindung für Ferroperiklas im Hoch-Spin Zustand, wohingegen Tief-Spin Ferroperiklas einen Trend zu einer mehr ionischen Fe-O Bindung auf-weist, was auf einen Bindungs-schwächenden Effekt des Spin-Wechsels hinweist. Der Übergang von Hoch- zu Tiefspin ist letztlich auf eine Zunahme der Ligandenfeldaufspaltungsenergie sowie eine abnehmende Spinpaarungsenergie von Hoch-Spin Fe2+ zurückzuführen. KW - optical properties KW - optische Eigenschaften KW - high pressure KW - Hochdruck KW - earth mantle KW - Erdmantel KW - diamond anvil cell KW - Diamantstempelzelle KW - ferropericlase KW - Ferroperiklas KW - spectroscopy KW - Spektroskopie Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-622166 ER - TY - JOUR A1 - Schjeide, Brit-Maren A1 - Schenke, Maren A1 - Seeger, Bettina A1 - Püschel, Gerhard T1 - Validation of a novel double control quantitative copy number PCR method to quantify off-target transgene integration after CRISPR-induced DNA modification JF - Methods and protocols : M&Ps N2 - In order to improve a recently established cell-based assay to assess the potency of botulinum neurotoxin, neuroblastoma-derived SiMa cells and induced pluripotent stem-cells (iPSC) were modified to incorporate the coding sequence of a reporter luciferase into a genetic safe harbor utilizing CRISPR/Cas9. A novel method, the double-control quantitative copy number PCR (dc-qcnPCR), was developed to detect off-target integrations of donor DNA. The donor DNA insertion success rate and targeted insertion success rate were analyzed in clones of each cell type. The dc-qcnPCR reliably quantified the copy number in both cell lines. The probability of incorrect donor DNA integration was significantly increased in SiMa cells in comparison to the iPSCs. This can possibly be explained by the lower bundled relative gene expression of a number of double-strand repair genes (BRCA1, DNA2, EXO1, MCPH1, MRE11, and RAD51) in SiMa clones than in iPSC clones. The dc-qcnPCR offers an efficient and cost-effective method to detect off-target CRISPR/Cas9-induced donor DNA integrations. KW - CRISPR editing validation KW - copy number analyses KW - homology-directed repair KW - homologous recombination deficiency Y1 - 2022 U6 - https://doi.org/10.3390/mps5030043 SN - 2409-9279 VL - 5 IS - 3 SP - 1 EP - 14 PB - MDPI CY - Basel, Schweiz ER - TY - JOUR A1 - Schlör, Anja A1 - Hirschberg, Stefan A1 - Ben Amor, Ghada A1 - Meister, Toni Luise A1 - Arora, Prerna A1 - Pöhlmann, Stefan A1 - Hoffmann, Markus A1 - Pfänder, Stephanie A1 - Eddin, Omar Kamal A1 - Kamhieh-Milz, Julian A1 - Hanack, Katja T1 - SARS-CoV-2 neutralizing camelid heavy-chain-only antibodies as powerful tools for diagnostic and therapeutic applications JF - Frontiers in Immunology N2 - Introduction: The ongoing COVID-19 pandemic situation caused by SARS-CoV-2 and variants of concern such as B.1.617.2 (Delta) and recently, B.1.1.529 (Omicron) is posing multiple challenges to humanity. The rapid evolution of the virus requires adaptation of diagnostic and therapeutic applications. Objectives: In this study, we describe camelid heavy-chain-only antibodies (hcAb) as useful tools for novel in vitro diagnostic assays and for therapeutic applications due to their neutralizing capacity. Methods: Five antibody candidates were selected out of a naïve camelid library by phage display and expressed as full length IgG2 antibodies. The antibodies were characterized by Western blot, enzyme-linked immunosorbent assays, surface plasmon resonance with regard to their specificity to the recombinant SARS-CoV-2 Spike protein and to SARS-CoV-2 virus-like particles. Neutralization assays were performed with authentic SARS-CoV-2 and pseudotyped viruses (wildtype and Omicron). Results: All antibodies efficiently detect recombinant SARS-CoV-2 Spike protein and SARS-CoV-2 virus-like particles in different ELISA setups. The best combination was shown with hcAb B10 as catcher antibody and HRP-conjugated hcAb A7.2 as the detection antibody. Further, four out of five antibodies potently neutralized authentic wildtype SARS-CoV-2 and particles pseudotyped with the SARS-CoV-2 Spike proteins of the wildtype and Omicron variant, sublineage BA.1 at concentrations between 0.1 and 0.35 ng/mL (ND50). Conclusion: Collectively, we report novel camelid hcAbs suitable for diagnostics and potential therapy. KW - camelid heavy-chain-only antibodies KW - single domain antibodies KW - nanobodies KW - SARS-CoV-2 KW - neutralization KW - Omicron Y1 - 2022 U6 - https://doi.org/10.3389/fimmu.2022.930975 SN - 1664-3224 SP - 1 EP - 14 PB - Frontiers Media SA CY - Lausanne, Schweiz ER -