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.     

Innere Bilder und beruflicher Lebensweg

This article gives an introduction into working with inner images. In the background of professional work and career there are inner images at work. They trigger which roles we take and which plays on which stages we choose or accept as meaningful. A Case study elaborately illustrates working with inner background images. Simple questions lead to relevant images, which influence professional life. A guide for interviewing and practical approaches can be found in the supplement.     

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.     

Construction of stationary state distributions for loss systems

A stationary state distribution will be constructed for a loss system G/G/m/0 without additional restrictive conditions. It will be shown by examples that for a given input there may exist several stationary state distributions. A sufficient and necessary criterion for the uniqueness will be formulated.     

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.     

Zu den Auswirkungen von Arbeitszeitmodellen im ärztlichen Dienst von Krankenhäusern

In 2004 a new working time law for physicians in hospitals was introduced, which has up until now been rarely researched in theory and is implemented in practice partially in form of new working time models, partially by relying on allowed variation rules within the law. Meanwhile, there are new discussions about changes of working time directives on the European level. This article aims to analyze the desired effects of the new working time law to decrease the workload, improve the possibilities of patient care and increase the working time satisfaction of physicians. To this end, a primary data collection is conducted in 15 hospitals and 35 hospital departments, generating 261 questionnaires, in order to empirically assess the theoretical model with the constructs working time model, workload, working time satisfaction, and possibilities of patient care using regression analyses. It can be shown that the new working time models decrease workload and enhance working time satisfaction of hospital physicians, but have no significant influence on the possibilities of patient care. These results are consistent for different ownerships and sizes of hospitals as well as for most services. No significant differences in the answers between various physician groups exist either.     

Produktdiversifizierung und Unternehmenserfolg: Nutzung der Forschungsdatenzentren der Statistischen ?mter

Zusammenfassung: Im Rahmen seiner industrie?konomischen Forschung beabsichtigt das DIW Berlin das Verhalten von Unternehmen auf den Produktm?rkten intensiver zu analysieren. In einem ersten Schritt soll der Zusammenhang zwischen Produktdiversifizierung, der Einführung neuer Produkte und dem Erfolg von Unternehmen im verarbeitenden Gewerbe untersucht werden. Dies soll mit Hilfe einer ?konometrischen Panelanalyse auf der Grundlage von Mikrodaten von Unternehmen erfolgen. Statt des in der Arbeitsmarktforschung üblichen Employer-Employee Datensatzes wird für diesen Zweck ein Producer-Product Datensatz ben?tigt. Erstmals sollen diese Mikrodaten im Rahmen einer Panelanalyse durch die Forschung ausgewertet werden. Dabei werden zwei getrennt durchgeführte Erhebungen, die Kostenstrukturerhebung und die Produktionserhebung, für einzelne Unternehmen zusammengefasst. M?glich wird dieses Forschungsvorhaben durch die Nutzung des auf Empfehlung der Kommission zur Verbesserung der informationellen Infrastruktur neu eingerichteten Forschungsdatenzentrums (FDZ). Das vorliegende Papier berichtet über das Forschungskonzept und die bisher erfolgten Schritte bei der Nutzung der Forschungsdatenzentren des Bundes und der L?nder am regionalen Standort Berlin.

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Summary: For a better understanding of the strategies of firms on their product markets, the DIW Berlin intends to intensify the analysis on the relationship between product diversification, including the introduction of new products and the success of firms. It is planned to do this by applying econometric panel methods on micro level data for German manufacturing enterprises. For this objective, it is necessary to create a producer-product database. This affords the merging of two different datasets of the system of surveys in manufacturing for Germany. The cost structure survey supplies information on the operating surplus of individual firms, while the production survey supplies the information on the goods produced by these firms. Conducting such an ambitious project has now been made possible in using the newly installed Research Data Centres (FDZ) for Germany. This paper gives an overview on the research project and on first experiences with the use of the local Research Data Centre in Berlin.

     

Arbeitsmarkt und Statistik: Chancen und Herausforderungen für die empirische Arbeitsmarktforschung

Ohne Zusammenfassung