Production of Sterile Neutrino Dark Matter and the 3.5 keV line

The recent observation of an X-ray line at an energy of 3.5 keV mainly from galaxy clusters has initiated a discussion about whether we may have seen a possible dark matter signal. If confirmed, this signal could stem from a decaying sterile neutrino of a mass of 7.1 keV. Such a particle could make up all the dark matter, but it is not clear how it was produced in the early Universe. In this letter we show that it is possible to discriminate between different production mechanisms with present-day astronomical data. The most stringent constraint comes from the Lyman-{\alpha} forest and seems to disfavor all but one of the main production mechanisms proposed in the literature, which is the production via decay of heavy scalar singlets. Pinning down the production mechanism will help to decide whether the X-ray signal indeed comprises an indirect detection of dark matter.Comment: Appendix added; slight change in distribution function, main results not affecte

Are there Gender-specific Preferences for Location Factors? A Grouped Conditional Logit-Model of Interregional Migration Flows in Germany

The article analyses the question whether women and men differ in their tastes for location factors. The question is answered by quantifying the impact of location characteristics on interregional migration flows across Germany. The analysis is based on a grouped conditional logit approach. We augment the framework by controlling for violation of the independence of irrelevant alternatives assumption and for overdispersion. As a result, we find no differences in terms of direction of impact. However, the regressions confirm gender differences in terms of intensity, particularly regarding regional wage levels and the availability of educational institutions.labour mobility, gender economics, regional migration, discrete choice model

Determinants of Female Migration – The Case of German NUTS 3 Regions

Our study examines the regional patterns and determinants of migration flows of young women. At the NUTS-3 regional level, i.e. the district level (Kreise), the German internal migration flows of the year 2005 are explored. From descriptive statistics it can be seen that peripheral regions in East Germany face the strongest migration deficit with respect to young women, whereas agglomerations in West Germany but also in the East benefit from an intense migration surplus within this group. An econometric analysis of determinants of regional migration flows gives evidence of the importance of labour market, family-related and educational migration motives. Generally speaking, young women tend to choose regions with good income and job opportunities, in addition they seem to be attracted by regions enabling an appropriate balance between family and career. Furthermore the existence of excellent educational facilities is a significant influence for young women’s migration. This educationally motivated type of migration generates a long lasting effect on the regional migration balance, especially when the educational opportunities in the destination region are associated with adequate career perspectives for high qualified female graduates. In view of considerable losses due to migration, the study shows various options for action. An important course of action is to incorporate policy measures improving regional employment and income opportunities. Secondly, extending vocational and academic offers addressed to women seems to be a suitable way to stimulate women’s immigration. Moreover, enhancing the social infrastructure, which contributes to a satisfactory work life balance, might attract young women or at least reduce the number of them leaving a region.spatial mobility, population economics

Domain organization of long autotransporter signal sequences

Bacterial autotransporters represent a diverse family of proteins that autonomously translocate across the inner membrane of Gram-negative bacteria via the Sec complex and across the outer bacterial membrane. They often possess exceptionally long N-terminal signal sequences. We analyzed 90 long signal sequences of bacterial autotransporters and members of the two-partner secretion pathway in silico and describe common domain organization found in 79 of these sequences. The domains are in agreement with previously published experimental data. Our algorithmic approach allows for the systematic identification of functionally different domains in long signal sequences. Keywords: bacterial autotransporter, sequence analysis, pattern, protein targeting, signal peptide, protein traffickin

Size and Development of the Shadow Economy and of Do-it-yourself Activities in Germany

This paper presents the first MIMIC (multiple indicator multiple causes) model estimate of the size and development of the shadow economy and of do-it-yourself (DIY) activities in Germany from 1970 to 2005. By 2005, they reached a level of about 17% and 4.94%. While the shadow economy has regularly increased over the years, DIY activities – though quite sizeable – have remained more or less constant since the early 1990s. The driving forces for the shadow economy are regulation and tax burden whereas for DIY activities, the level of unemployment is the main factor.shadow economy, do-it-yourself activities, tax burden, regulation, domestic currency in circulation, unemployment, MIMIC models

Satisfaction with Democracy and Collective Action Problems: The Case of the Environment

Using modern methods for analyzing multi-level data, we find that, by and large, citizens of OECD countries are more satisfied with the way democracy works in their country if more environmental policies are in place and if environmental quality is higher. We also document that parents care about carbon dioxide emissions more than non-parents and that those with a high willingness to pay for environmental quality deplore intervention through government policies.Collective action problems, environmental economics and policy, satisfaction with democracy