Competing definitions of justice in Plato’s Republic and Aristotle’s Politics indicate the existence of two distinct economic systems with different normative priorities. The three-class society of the Platonic economy (guardians, auxiliaries, producers) gives rise to guardians who by virtue are expected to enforce output targets on producers directly or through auxiliaries. The three-class society of the Aristotelian economy (rich, middle, poor) facilitates the emergence of different ruling coalitions and compensates efficiency losses of vertical production processes with political gains derived from representative governance. In the Aristotelian economy, the middle class is better off than in the Platonic economy (auxiliaries), because a just society (polity) is achieved under its rule. I argue that the equilibrium solutions of the Platonic and Aristotelian systems provide the normative foundations for the distinction between plan and market.

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.

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.

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.

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.

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.