Energy crop production in an urban area: a comparison of habitat types and land use forms targeting economic benefits and impact on species diversity

In urban areas, the potential of biomass production is rarely utilized, although many biomass sources are located in cities, ranging from road margins to public parks. There is, however, increasing interest in these potential biomass sources, as they are close to consumers and provide options to reduce maintenance costs of urban green areas. We analyzed the costs and benefits of utilizing biomass, and compared it to the biodiversity maintained on 17 urban land use forms the Ruhr Metropolitan Area (Germany). Economic costs and benefits were reflected by contribution margins, while biodiversity was measured by species numbers of plants, birds and butterflies. For the 17 land use types, there is a weak overall correlation between contribution margins and species numbers. However, this is mainly due to the two land use forms with the highest contribution margins (cultivation of energy maize and fertilized grassland), which are characterized by the lowest species numbers. For the remaining cases, there is no relationship between contribution margins and species numbers. Comparatively high contribution margins and high mean species numbers were observed for road margins, industrial fallows with wood cutting for biogas production and water-influenced grassland mown traditionally. We conclude that biomass production and the maintenance of urban biodiversity is not necessarily a contradiction.     

Runtime and memory consumption analyses for machine learning R programs

R is a multi-paradigm language with a dynamic type system, different object systems and functional characteristics. These characteristics support the development of statistical algorithms at a high level of abstraction. Although R is commonly used in the statistics domain a big disadvantage are its runtime problems when handling computation-intensive algorithms. Especially in the domain of machine learning the execution of pure R programs is often unacceptably slow. Our long-term goal is to resolve these issues and in this contribution we used the traceR tool to analyse the bottlenecks arising in this domain. Here we measured the runtime and overall memory consumption on a well-defined set of classical machine learning applications and gained detailed insights into the performance issues of these programs.     

The senator’s tale: the development of Bremen’s bourgeoisie in the post-1945 era

Were members of the German bourgeoisie capable of forming the foundation for a new self-understanding of post-1945German society? Or did they prove to be unsuited as agents of Germany’s new beginning? This article seeks to answer these questions by focusing on historical developments in the early phase of the Federal Republic of Germany as reflected in the biography of one prominent representative of the German bourgeoisie. Theodor Spitta, who was born in 1873, was elected in 1911as a senator for life in the government of the Free Hanse City of Bremen. Spitta was an outstanding representative of a generation socialized under the last German Kaiser, a generation which perceived itself as part of a politically liberal Bremen bourgeoisie. He feared the gradual decline, indeed the disintegration of his class. None the less – or perhaps for that very reason – he committed himself to the goal of restoring a regionally specific form of bourgeois life in the city of Bremen. Although Spitta declared a ‘farewell to the bourgeoisie’ in his autobiographical texts, that did not prevent him from actively pursuing the revival of a unique urban-bourgeois ‘spirit’. This spirit was to serve as a tool in promoting Bremen’s central political goal in post-1945Germany: the preservation of the city-state’s unique status within Germany’s federal system.     

Success factors of management consulting

Management consulting as a service has become part of almost every medium to big company’s daily business. Despite management consulting’s high practical relevance the scientific discussion of this discipline is relatively young and needs to advance. Notably, there is little empirical research that focuses on the conceptualization and operationalization of management consulting’s success factors from a client perspective. Therefore, in this article we theoretically conceptualize and subsequently operationalize critical success factors of management consulting. Also, we examine those factors’ particular impact on management consulting success. Based on a survey of 255 companies and structural equation modeling, we show that six out of seven theoretically derived success factors have a significant positive effect on management consulting success. In particular, Consultant Expertise, Intensity of Collaboration and Common Vision have a strong impact on the performance of management consulting.     

Schulverweigerung

The aim of this article is to describe the extent of truancy in Cologne and to identify the relevant predictors. Hypotheses are deduced from classical deviance theories (control theory, amomy theory, theory of urban subcultures) and tested empirically. Our analysis is based on a survey of pupils in Cologne from grade 8 to 10 which was conducted in 1999 by the Max Planck Institute for Foreign and International Criminal Law in Freiburg. Our results show that 7.9 percent of all respondends can be defined as truants. Boys play truant more than girls, and the higher the age, the more pupils bunk off school. More important than gender and age is the type of secondary school. We find the highest amount of truants at Hauptschulen and Sonderschulen. It is shown that truancy is a multidimensional phenomenon that cannot be explained by just one single theory.     

Fiscal equalisation: Principles and an application to the European Union

The paper derives a normative model for partial fiscal equalisation based on a number of axioms and makes special allowance for the existence of a specific fiscal need in the jurisdictions. A simple version of this idealised equalisation scheme relates net contributions to the equalisation funds to deviations of a jurisdictions gross income from average gross income and a jurisdictions specific needs from average specific needs. The theoretical model is then empirically tested for the case of the European Union using data from 1986–97. It is found that most restrictions of the model appear to hold, in particular, relatively richer countries contribute more and those with greater fiscal needs, approximated by the importance of the agricultural sector, pay less. However, in the EU, an adjustment of net payments to changes in the actual importance of the specific fiscal need for a country is lacking.The paper was presented at the CESifo Area Conference on Public Sector Economics 2001 in Munich and at a research seminar in Berlin. Thanks to the participants, Matthias Brückner, Johann Brunner, Jeremy Edwards, Friedrich Heinemann, Eckhard Janeba, Roland Strausz, and Alfons Weichenreider for helpful comments. Special thanks to an anonymous referee for many detailed suggestions. All remaining errors are our own.