University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Context (language use) & Politics. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

Comprehensive Analysis of Human Endogenous Retrovirus Transcriptional Activity in Human Tissues with a Retrovirus-Specific Microarray

Abstract: Retrovirus-like sequences account for 8 to 9% of the human genome. Among these sequences, about 8,000 pol-containing proviral elements have been identified to date. As part of our ongoing search for active and possibly disease-relevant human endogenous retroviruses (HERVs), we have recently developed an oligonucleotide-based microarray. The assay allows for both the detection and the identification of most known retroviral reverse transcriptase (RT)-related nucleic acids in biological samples. In the present study, we have investigated the transcriptional activity of representative members of 20 HERV families in 19 different normal human tissues. Qualitative evaluation of chip hybridization signals and quantitative analysis by real-time RT-PCR revealed distinct HERV activity in the human tissues under investigation, suggesting that HERV elements are active in human cells in a tissue-specific manner. Most active members of HERV families were found in mRNA prepared from skin, thyroid gland, placenta, and tissues of reproductive organs. In contrast, only few active HERVs were detectable in muscle cells. Human tissues that lack HERV transcription could not be found, confirming that human endogenous retroviruses are permanent components of the human transcriptome. Distinct activity patterns may reflect the characteristics of the regulatory machinery in these cells, e.g., cell type-dependent occurrence of transcriptional regulatory factors.

Labor Markets and Economic Incorporation among Recent Immigrants in Europe

Abstract: The questions asked in the paper are whether and to what extent the employment situation among recent third-country immigrants differs across European Union countries and how it is related to these countries' labor market characteristics. The European Labor Force Survey data for the 1990s are used to disentangle the roles that the individual characteristics of immigrants, on the one hand, and the structural features of the receiving societies, on the other, play in the process of immigrants' labor market integration. The results of multilevel regression analyses confirm that in receiving countries with stronger demand for low-skilled labor, unprivileged immigrants are less disadvantaged at employment entry. Among men immigrants' employment disadvantages are found to be lower in liberal welfare states marked by their flexible labor markets.

Rearchitecting the UML infrastructure

Abstract: Metamodeling is one of the core foundations of computer-automated multiparadigm modeling. However, there is currently little agreement about what form the required metamodeling approach should take and precisely what role metamodels should play. This article addresses the problem by first describing some fundamental problems in the industry's leading metamodeling technology, the UML framework, and then explaining how this framework could be rearchitected to overcome these problems. Three main issues are identified in the current framework: the dual classification problem arising from the need to capture both the logical and physical classification of model elements, the class/object duality problem arising from the need to capture both the classlike and objectlike facets of some model elements, and the replication of concepts problem arising from the need to define certain concepts multiple times. Three main proposals for rearchitecting the UML framework to overcome these problems are then presented: the separation of logical and physical classification dimensions, the unification of the class and object facets of model elements, and the enhancement of the instantiation mechanism to allow definitions to transcend multiple levels. The article concludes with a discussion of other practical issues involved in rearchitecting the UML modeling framework in the proposed way.

Real options valuation: the new frontier in R&D project evaluation?

Abstract: The real options approach has recently received growing attention in R&D and Technology Management research. Recent empirical findings by Ellis (1997) and Busby and Pitts (1997) also report growing attention and use in practical investment decisions. However, there is a certain concern about the applicability to a wide range of R&D related problems. The theoretical base behind options valuation is derived from the capital markets and thus assumes market conditions that are closer to the theoretical construct of ‘perfect competition’ than most other settings. Even under these conditions, several assumptions made and difficulties left are subject to controversial discussions. Of course these problems even gain importance when the R&D environment with its discontinuities and lack of regulation or institutionalized trade is assumed. This paper describes some basic properties of the real options approach and sheds light on existing problems for the application in R&D project evaluation. On the other hand, roads to application of the method are shown using the Geske model of option evaluation. One main goal of the paper is to broaden and deepen the discussion on real option models in R&D and Technology Management, which has in some cases been limited to stressing the advantages of the method rather than reflecting on applicability and concrete way of application of the method.