We present the study of the dynamics of a two-ring waveguide structure with space-dependent coupling, linear gain and nonlinear absorption; the system that can be implemented in polariton condensates, optical waveguides and nanocavities. We show that by turning on and off local coupling between rings, one can selectively generate a permanent vortex in one of the rings. We find that due to the modulation instability, it is also possible to observe several complex nonlinear phenomena, including spontaneous symmetry breaking, stable inhomogeneous states with an interesting structure of currents flowing between rings, the generation of stable symmetric and asymmetric circular flows with various vorticities, etc. The latter can be created in pairs (for relatively narrow coupling length) or as a single vortex in one of the channels, which later alternates between channels.Weniger anzeigen
With over 72 years having elapsed since the liberation of the Nazi concentration and extermination camps, what is the current status of teaching about the Holocaust at German universities? What do students, within the framework of their studies, learn about the Holocaust and its aftermath? To what extent and in which disciplines is the topic taught? What special challenges arise from German responsibility for the Holocaust? Does the higher education system in Germany have any special features that affect the way of teaching? Up till now there have been no comprehensive studies of all these questions. Unlike the status and development of Holocaust education at secondary schools in Germany, teaching at German universities on the subject has rarely been a topic of academic research. The present study intends to close this gap, by ascertaining, describing, and pointing out special features and trends in the actual state of affairs of teaching about the Holocaust at universities in Germany. By means of a two-stage survey procedure, combining an empirical evaluation of academic calendars with a content analysis of interviews with experts, the status quo is described both quantitatively and qualitatively, thus creating a differentiated picture of academic teaching about the Holocaust in Germany.Weniger anzeigen
Research on the conjunction of business elites and sustainable development fascinates practitioners and international organizations but faces methodological and data collection challenges within academia. Firstly, studies on corporate sustainability have promptly increased but have been extremely focused on an organizational level of analysis, which inhibits figuring out whether business decisions have an impact at the macro or societal level. Secondly, major policy recommendations on sustainable development point to the creation of networks and partnerships among business elites, governments and civil organizations but it is largely ignored which specific type of network configuration goes along with sustainable development. Thirdly, the literature on sustainable development often considered business elites as homogenous and concentrated, even though conflicting views exist regarding aspects of sustainable development. Finally, the influence of business elites on environmental, social and economic policies has been more supposed than empirically demonstrated. Past research has been unable to overcome these challenges in part due to insufficient data clarifying the full breadth of business elite connections with political and civil organizations nationally and transnationally, and the lack of a combination of analytical tools for analyzing multilevel characteristics and actions. The present paper proposes a research agenda to comprehend the role of business elites in sustainable development. Future studies should use network analysis as leverage, uncover the networks among business and political elites, focus on Latin American economies and regions, bypass case studies and develop cross-national and transnational analysis, and turn to a combination of causal methods.Weniger anzeigen
Using a state-of-the-art chemistry–climate model we investigate the future change in stratosphere–troposphere exchange (STE) of ozone, the drivers of this change, as well as the future distribution of stratospheric ozone in the troposphere. Supplementary to previous work, our focus is on changes on the monthly scale. The global mean annual influx of stratospheric ozone into the troposphere is projected to increase by 53 % between the years 2000 and 2100 under the RCP8.5 greenhouse gas scenario. The change in ozone mass flux (OMF) into the troposphere is positive throughout the year with maximal increase in the summer months of the respective hemispheres. In the Northern Hemisphere (NH) this summer maximum STE increase is a result of increasing greenhouse gas (GHG) concentrations, whilst in the Southern Hemisphere(SH) it is due to equal contributions from decreasing levels of ozone depleting substances (ODS) and increasing GHG concentrations. In the SH the GHG effect is dominating in the winter months. A large ODS-related ozone increase in the SH stratosphere leads to a change in the seasonal breathing term which results in a future decrease of the OMF into the troposphere in the SH in September and October. The resulting distributions of stratospheric ozone in the troposphere differ for the GHG and ODS changes due to the following: (a) ozone input occurs at different regions for GHG- (midlatitudes) and ODS-changes (high latitudes); and (b) stratospheric ozone is more efficiently mixed towards lower tropospheric levels in the case of ODS changes, whereas tropospheric ozone loss rates grow when GHG concentrations rise. The comparison between the moderate RCP6.0 and the extreme RCP8.5 emission scenarios reveals that the annual global OMF trend is smaller in the moderate scenario, but the resulting change in the contribution of ozone with stratospheric origin (O3s) to ozone in the troposphere is of comparable magnitude in both scenarios. This is due to the larger tropospheric ozone precursor emissions and hence ozone production in the RCP8.5 scenario.Weniger anzeigen
Hyperbranched polyglycerol (hPG) has been used as a multivalent scaffold to develop a series of nanocarriers capable of high-affinity encapsulation of copper (Cu). A rationally selected set of Cu-complexing motifs has been conjugated to hPG hydroxyl groups to render the constructs potentially usable as exogenous sources of Cu for addressing different pathological conditions associated with Cu-deficiency. We have utilized a newly discovered route to attach Cu-binding domains exclusively within a hPG core by selective differentiation between the primary and secondary hydroxyl groups of the polyol. These hPG-derivatives were found to form a stable complex with Cu ions depending on the type of immobilized ligands and corresponding degree of functionalization. In addition, these Cu-bearing nano-complexes demonstrated moderately cationic surface charge resulting in adjustable protein-binding characteristics and low cellular toxicity profile. We envision that these Cu-loaded hPG nanocarriers can be used as a stable platform to transport the metal ion across the systemic circulation to supply bioavailable quantity of Cu in disease-afflicted tissues.Weniger anzeigen
The capability of lipid bilayers to exhibit fluid-phase behavior is a fascinating property, which enables, for example, membrane-associated components, such as lipids (domains) and transmembrane proteins, to diffuse within the membrane. These diffusion processes are of paramount importance for cells, as they are for example involved in cell signaling processes or the recycling of membrane components, but also for recently developed analytical approaches, which use differences in the mobility for certain analytical purposes, such as in-membrane purification of membrane proteins or the analysis of multivalent interactions. Here, models describing the Brownian motion of membrane inclusions (lipids, peptides, proteins, and complexes thereof) in model bilayers (giant unilamellar vesicles, black lipid membranes, supported lipid bilayers) are summarized and model predictions are compared with the available experimental data, thereby allowing for evaluating the validity of the introduced models. It will be shown that models describing the diffusion in freestanding (Saffman-Delbrück and Hughes-Pailthorpe-White model) and supported bilayers (the Evans-Sackmann model) are well supported by experiments, though only few experimental studies have been published so far for the latter case, calling for additional tests to reach the same level of experimental confirmation that is currently available for the case of freestanding bilayers.Weniger anzeigen
One of the most prominent asymmetric features of the southern hemispheric (SH) circulation is the split jet over Australia and New Zealand in austral winter. Previous studies have developed indices to detect the degree to which the upper-level midlatitude westerlies are split and investigated the relationship between split events and the low-frequency teleconnection patterns, viz. the Antarctic Oscillation (AAO) and the El Niño–Southern Oscillation (ENSO). As the results were inconsistent, the relationship between the wintertime SH split jet and the climate variability indices remains unresolved and is the focus of this study.
Until now, all split indices' definitions were based on the specific region where the split jet is recognizable. We consider the split jet as hemispheric rather than a regional feature and propose a new, hemispherical index that is based on the principal components (PCs) of the zonal wind field for the SH winter. A linear combination of PC2 and PC3 of the anomalous monthly (JAS) zonal wind is used to identify split-jet conditions.
In a subsequent correlation analysis, our newly defined PC-based split index (PSI) indicates a strong coherence with the AAO. However, this significant relationship is unstable over the analysis period; during the 1980s, the AAO amplitude was higher than the PSI, and vice versa in the 1990s. It is probable that the PSI, as well as the AAO, underlie low-frequency variability on the decadal to centennial timescales, but the analyzed period is too short to draw these conclusions. A regression analysis with the Multivariate ENSO Index points to a nonlinear relationship between PSI and ENSO; i.e., split jets occur during both strong positive and negative phases of ENSO but rarely under "normal" conditions. The Pacific South American (PSA) patterns, defined as the second and third modes of the geopotential height variability at 500 hPa, correlate poorly with the PSI (rPSA − 1 ≈ 0.2 and rPSA − 2 = 0.06), but significantly with the individual components (PCs) of the PSI, revealing an indirect influence on the SH split-jet variability.
Our study suggests that the wintertime SH split jet is strongly associated with the AAO, while ENSO is to a lesser extent connected to the PSI. We conclude that a positive AAO phase, as well as both flavors of ENSO and the PSA-1 pattern produce favorable conditions for a SH split event.Weniger anzeigen
We investigate a reduced point vortex model for statistical and dynamical analyses of atmospheric blocking phenomena. Thereby, we consider High-over-low and Omega blocking as relative equilibria of two and three point vortices. Under certain conditions, such point vortex systems move westward opposing the mean westerly flow and hence can become stationary. Based on the kinematic vorticity number, two novel, independent methods, the contour and the trapezoid method, are introduced in order to identify the vortices that form the blocking pattern, their local positions and circulation magnitudes. While the contour method takes into account the observed stationarity of blocking, the trapezoid method minimizes the total circulation of the vortex system following point vortex theory. Using an instantaneous blocking index, a total number of 347 blocking periods were identified in NCEP-NCAR Reanalysis data for the Euro-Atlantic region during the time period 1990–2012. This procedure provides the basis to corroborate the applicability of the point vortex model to atmospheric blocking in a statistical framework. The calculated translation speed of point vortex systems associated with the atmospheric blocking appears to match the zonal mean velocity reasonably well. This model explains the stationary behaviour of blocking patterns. A comparison between the theoretical and a statistical model further reveals that the circulation of the blocking high follows the principles of the point vortex model to a large extent. However, the low-pressure systems behave more variable. Moreover, the stability of point vortex equilibria is analysed regarding the relative distances by considering linear stability analysis and simulations. This reveals that the point vortex blocking model corresponds to an unstable saddle point. Furthermore, we take viscosity and a Brownian motion into account to simulate the influence of the smaller, subgrid-scale disturbances. As a result, a clustering near the equilibrium state emerges indicating the persistence of the atmospheric blocking pattern.Weniger anzeigen
Climate simulations are the fuel to drive hydrological models that are used to assess the impacts of climate change and variability on hydrological parameters, such as river discharges, soil moisture, and evapotranspiration. Unlike with cars, where we know which fuel the engine requires, we never know in advance what unexpected side effects might be caused by the fuel we feed our models with. Sometimes we increase the fuel's octane number (bias correction) to achieve better performance and find out that the model behaves differently but not always as was expected or desired. This study investigates the impacts of projected climate change on the hydrology of the Upper Blue Nile catchment using two model ensembles consisting of five global CMIP5 Earth system models and 10 regional climate models (CORDEX Africa). WATCH forcing data were used to calibrate an eco-hydrological model and to bias-correct both model ensembles using slightly differing approaches. On the one hand it was found that the bias correction methods considerably improved the performance of average rainfall characteristics in the reference period (1970–1999) in most of the cases. This also holds true for non-extreme discharge conditions between Q20 and Q80. On the other hand, bias-corrected simulations tend to overemphasize magnitudes of projected change signals and extremes. A general weakness of both uncorrected and bias-corrected simulations is the rather poor representation of high and low flows and their extremes, which were often deteriorated by bias correction. This inaccuracy is a crucial deficiency for regional impact studies dealing with water management issues and it is therefore important to analyse model performance and characteristics and the effect of bias correction, and eventually to exclude some climate models from the ensemble. However, the multi-model means of all ensembles project increasing average annual discharges in the Upper Blue Nile catchment and a shift in seasonal patterns, with decreasing discharges in June and July and increasing discharges from August to November.Weniger anzeigen
Extra-tropical cyclones in the subantarctic play a central role in the poleward transport of heat and moisture into Antarctica, with the latter being a key component of the mass balance of the Antarctic ice sheet. As the climate in this region undergoes substantial changes, it is anticipated that the character of these synoptic features will change. There are a number of different methods used to identify and track cyclones, which can potentially lead to different conclusions as to cyclone variability and trends, and mechanisms which drive these features. Given this, it is timely to assess the level of consensus among 14 state-of-the-art cyclone identification and tracking methods. We undertake this comparison with the ERA-Interim data-set for the period 1979–2008 and find large differences in the number of tracks identified by different methods, but the spatial patterns of the system density broadly agree. Links between large-scale modes of variability, such as the Southern Annular Mode (SAM), and subantarctic cyclones as suggested in the literature are confirmed by our analysis. Trends in the number of cyclone tracks show a more diverse picture. Robust trends are identified by almost all methods for austral summer over the region south to 60°S, mainly due to the strong relation to SAM, whereas in austral winter the methods disagree in the statistical significance of the trends. The agreement among the methods is greater when the comparison is confined to the stronger cyclones. This is confirmed by a moisture flux analysis associated with these strong synoptic systems. Our results indicate that multiple cyclone identification and tracking methods should be used to obtain robust conclusions for trends in cyclone characteristics as well as their relation to the large-scale circulation in the subantarctic region.Weniger anzeigen
A new generation of library systems is about to replace the so-called integrated library systems, which are beginning to fade. The library services platforms Alma, FOLIO and Worldshare Management Services (WMS), which are already in productive operation in some places, were examined with regard to their suitability for use in German libraries. The technical framework conditions and characteristics of those library management systems were studied and inventorized, so that they could be evaluated according to objective criteria. Based on that evaluation, recommendations were drawn up for libraries. The foundation for the investigation is made up of three components: First, German libraries’ requirements in relation to the new generation of systems were distilled from a broad range of literature and categorized. Furthermore, interviews were conducted with experts, addressing questions of system administration. Also, a widely distributed user survey was carried out to collect opinions on the performance of the systems in productive operation. The systems that are already in productive operation (Alma and WMS) can be employed to implement standard processes and integration options so that standard tasks can be accomplished. However, there are still unresolved issues with regard to nationally established and cooperatively maintained systems (federation catalogs, Zeitschriftendatenbank, Elektronische Zeitschriftenbibliothek). The main advantage of library services platforms lies in the possibility of managing print and electronic resources in one system. The systems conform to German and European regulations and laws in security aspects, but providers still have to clarify their compliance regarding the General Data Protection Regulation (GDPR). Problems arise from cloud computing and the associated remote and distributed data storage: Libraries can access their own data through application programming interfaces only. Finally, no increases in efficiency or cost reductions have been achieved so far.Weniger anzeigen
In the spring oilseed rape (OSR) cultivar ‘Mozart’ grown under optimal N supply (NO) or mild N deficiency (NL) the transcriptome changes associated with progressing age until early senescence in developmentally old lower canopy leaves (leaf #4) and younger higher canopy leaves (leaf #8) were investigated. Twelve weeks old NO and NL plants appeared phenotypically and transcriptomically identical, but thereafter distinct nutrition-dependent differences in gene expression patterns in lower and upper canopy leaves emerged. In NO leaves #4 of 14-week-old compared to 13-week-old plants, ∼600 genes were up- or downregulated, whereas in NL leaves #4 ∼3000 genes were up- or downregulated. In contrast, in 15-week-old compared to 13-week-old upper canopy leaves #8 more genes were up- or downregulated in optimally N-supplied plants (∼2000 genes) than in N-depleted plants (∼750 genes). This opposing effect of N depletion on gene regulation was even more prominent among photosynthesis-related genes (PSGs). Between week 13 and 14 in leaves #4, 99 of 110 PSGs were downregulated in NL plants, but none in NO plants. In contrast, from weeks 13 to 16 in leaves #8 of NL plants only 11 PSGs were downregulated in comparison to 66 PSGs in NO plants. Different effects of N depletion in lower versus upper canopy leaves were also apparent in upregulation of autophagy genes and NAC transcription factors. More than half of the regulated NAC and WRKY transcription factor, autophagy and protease genes were specifically regulated in NL leaves #4 or NO leaves #8 and thus may contribute to differences in senescence and nutrient mobilization in these leaves. We suggest that in N-deficient plants the upper leaves retain their N resources longer than in amply fertilized plants and remobilize them only after shedding of the lower leaves.Weniger anzeigen
The Castel Giorgio-Torre Alfina (CG-TA, central Italy) is a geothermal reservoir whose fluids are hosted in a carbonate formation at temperatures ranging between 120°C and 210°C. Data from deep wells suggest the existence of convective flow. We present the 3D numerical model of the CG-TA to simulate the undisturbed natural geothermal field and investigate the impacts of the exploitation process. The open source finite-element code OpenGeoSys is applied to solve the coupled systems of partial differential equations. The commercial software FEFLOW® is also used as additional numerical constraint. Calculated pressure and temperature have been calibrated against data from geothermal wells. The flow field displays multicellular convective patterns that cover the entire geothermal reservoir. The resulting thermal plumes protrude vertically over 3 km at Darcy velocity of about m/s. The analysis of the exploitation process demonstrated the sustainability of a geothermal doublet for the development of a 5 MW pilot plant. The buoyant circulation within the geothermal system allows the reservoir to sustain a 50-year production at a flow rate of 1050 t/h. The distance of 2 km, between the production and reinjection wells, is sufficient to prevent any thermal breakthrough within the estimated operational lifetime. OGS and FELFOW results are qualitatively very similar with differences in peak velocities and temperatures. The case study provides valuable guidelines for future exploitation of the CG-TA deep geothermal reservoir.Weniger anzeigen
Staphylococcus aureus is the most common contagious pathogen associated with bovine subclinical mastitis. Current diagnosis of S. aureus mastitis is based on bacteriological culture of milk samples and somatic cell counts, which lack either sensitivity or specificity. Identification of milk proteins that contribute to host defense and their variable responses to pathogenic stimuli would enable the characterization of putative biomarkers of subclinical mastitis. To accomplish this, milk whey samples from healthy and mastitic dairy cows were analyzed using a label-free quantitative proteomics approach. In total, 90 proteins were identified, of which 25 showed significant differential abundance between healthy and mastitic samples. In silico functional analyses indicated the involvement of the differentially abundant proteins in biological mechanisms and signaling pathways related to host defense including pathogen-recognition, direct antimicrobial function, and the acute-phase response. This proteomics and bioinformatics analysis not only facilitates the identification of putative biomarkers of S. aureus subclinical mastitis but also recapitulates previous findings demonstrating the abundance of host defense proteins in intramammary infection. All mass spectrometry data are available via ProteomeXchange with identifier PXD007516.Weniger anzeigen
The poor healing potential of tendons is still a clinical problem, and the use of Platelet Rich Plasma (PRP) was hypothesized to stimulate healing. As the efficacy of PRPs remains unproven, platelet lysate (PL) could be an alternative with its main advantages of storage and characterization before use. Five different blood products were prepared from 16 male donors: human serum, two PRPs (Arthrex, (PRP-ACP); RegenLab (PRP-BCT)), platelet concentrate (apheresis, PC), and PL (freezing-thawing destruction of PC). Additionally, ten commercial allogenic PLs (AlloPL) from pooled donors were tested. The highest concentration of most growth factors was found in AlloPL, whereas the release of growth factors lasted longer in the other products. PRP-ACP, PRP- BCT, and PC significantly increased cell viability of human tenocyte-like cells, whereas PC and AlloPL increased Col1A1 expression and PRP-BCT increased Col3A1 expression. MMP-1, IL-1β, and HGF expression was significantly increased and Scleraxis expression decreased by most blood products. COX1 expression significantly decreased by PC and AlloPL. No clear positive effects on tendon cell biology could be shown, which might partially explain the weak outcome results in clinical practice. Pooled PL seemed to have the most beneficial effects and might be the future in using blood products for tendon tissue regeneration.Weniger anzeigen
Gutachten zum schweizerischen Unterhaltsrecht für das Amtsgericht Perleberg. Die Parteien streiten über die Höhe des Kindesunterhalts. Die minderjährige Klägerin ist Deutsche. Der Kindesvater ist deutscher Staatsangehöriger mit Wohnsitz und Arbeitsplatz im schweizerischen Kanton Thurgau.