Exact ground state of the generalized three-dimensional Shastry-Sutherland model

We generalize the Shastry-Sutherland model to three dimensions. By representing the model as a sum of the semidefinite positive projection operators, we exactly prove that the model has exact dimer ground state. Several schemes for constructing the three-dimensional Shastry-Sutherland model are proposed.Comment: Latex, 3 pages, 5 eps figure

Local Determinants of Crime: Distinguishing between Resident and Non-Resident Offenders

The paper revisits the local determinants of crime using a spatial model distinguishing between resident and non-resident offenders. Employing data for German municipalities, the model is estimated by means of a spatial GMM approach. Focusing on resident offenders legal earnings opportunities and the expected gain from offenses are found to be important determinants of crime. Also the socio-economic background in terms of unemployment, poverty, and inequality proves significant for both property and violent crime. Whereas local inequality only shows an effect on crime committed by resident offenders, crime committed by non-resident offenders is shown to be significantly related to the characteristics in adjacent municipalities such as unemployment and income.Crime, Causes of Crime, Cross-Sectional Study, Spatial Econometrics, Crime Spillovers, Neighborhood Effects, Instrumental Variables

News and Correlations of CEEC-3 Financial Markets

We investigate conditional correlations between six CEEC-3 financial markets estimated by DCC-MGARCH models. In general, the highest correlations exist between Hungary and Poland in foreign exchange and stock markets. Short-term money markets are rather isolated from each other. We find that the associations of CEEC-3 exchange rates versus the euro are weaker than those versus the US dollar. The persistence of the effect of shocks on the timevarying correlations is strongest for foreign exchange and stock markets, indicating a tendency toward contagion. In searching for the origins of financial market volatility in the CEEC-3, we uncover some evidence of Granger-causality on the foreign exchange markets. Finally, using a pool model, we investigate the impact of euro area, US, and CEEC-3 news on the correlations. Apart from ECB monetary policy news, we observe no broad effects of international news on correlations; instead, local news exerts an influence, which suggests adominance of country- or market-specific circumstances.Financial markets, Czech Republic, Hungary, Poland, political news, macroeconomic shocks, contagion, DCC-MGARCH

Determinants of European Stock Market Integration

We analyse the determinants of stock market integration among EU member states for the period 1999–2007. First, we apply bivariate DCC-MGARCH models to extract dynamic conditional correlations between European stock markets, which are then explained by interest rate spreads, exchange rate risk, market capitalisation, and business cycle synchronisation in a pooled OLS model. By grouping the countries into euro area countries, “old” EU member states outside the euro area, and new EU member states, we also evaluate the impact of euro introduction and the European unification process on stock market integration. We find a significant trend toward more stock market integration, which is enhanced by the size of relative and absolute market capitalisation and hindered by foreign exchange risk between old member states and the euro area. Interest rate spreads and business cycle synchronisation do not appear to play an important role in explaining equity market integration.Stock Market Integration, European Unification, DCC-MGARCH model

Quality of Life in the Regions - Results for German Counties

In order to assess differences in living conditions across German regions we apply the hedonic approach of Rosen (1979) and Roback (1982) to land-price and wage differences across Germany’s counties. Employing a recent survey of more than half a million Germans on a wide range of social and political issues we confirm that differences in amenities give rise to substantial differences in land prices. With regard to wages, however, we find only little effects of amenities. Relying on the land-price effects we assess the quality of life in each of the German counties and provide a comprehensive ranking.Land prices; regional income differentials; hedonic regression; quality of life; compensating wage differentials

Are We Spending Too Many Years in School? Causal Evidence of the Impact of Shortening Secondary School Duration

This paper analyzes the impact of shortening the duration of secondary schooling on the accumulation of human capital. In 2003, an educational policy reform was enacted in Saxony-Anhalt, a German state, providing a natural experimental setting. The thirteenth year of schooling was eliminated for those students currently attending the ninth grade. Tenth grade students were unaffected. The academic curriculum remained almost unaltered. Primary data collected from the double cohort of 2007 Abitur graduates reveals signficantly negative effects for both genders in mathematics. Only females were negatively effected in English and the results obtained in German literature were statistically insignificant.student performance, school duration, learning intensity, natural experiment

Labor Market Effects of Economic Integration - The Impact of Re-Unification in German Border Regions

The paper argues that economic integration causes problems for the labor market of high-wage countries due to cross-border labor mobility and the accompanying increase in labor supply. Empirical evidence is provided from an analysis of regional labor market effects of German re-unification. In the aftermath of the re-unification shock, despite some gain in employment, border regions situated on the former German-German border are found to have experienced a fall in the relative wage position and an increase in unemployment relative to other West-German regions. As this points to adverse labor supply effects for resident workers due to cross-border labor mobility, this result is bad news for EU regions situated on the border with the Accession countries in Central and Eastern Europe.economic integration, border regions, EU enlargement, German re-unification, differences in differences estimation

Multiple imputation of right-censored wages in the German IAB Employment Sample considering heteroscedasticity

"In many large data sets of economic interest, some variables, as wages, are top-coded or right-censored. In order to analyze wages with the German IAB employment sample we first have to solve the problem of censored wages at the upper limit of the social security system. We treat this problem as a missing data problem and derive new multiple imputation approaches to impute the censored wages by draws of a random variable from a truncated distribution based on Markov chain Monte Carlo techniques. In general, the variation of income is smaller in lower wage categories than in higher categories and the assumption of homoscedasticity in an imputation model is highly questionable. Therefore, we suggest a new multiple imputation method which does not presume homoscedasticity of the residuals. Finally, in a simulation study, different imputation approaches are compared under different situations and the necessity as well as the validity of the new approach is confirmed." (Author's abstract, IAB-Doku) ((en))Lohnhöhe, Daten, Datenaufbereitung - Methode, angewandte Statistik, mathematische Statistik, Schätzung, Markov-Ketten, Monte-Carlo-Methode, IAB-Beschäftigtenstichprobe, Imputationsverfahren, Westdeutschland, Bundesrepublik Deutschland

QR code awareness in Stockholm, Sweden

This tech report describes the findings of a street survey on awareness of QR codes (2D barcodes) of the general public in Stockholm, Sweden. 108 passers-by were surveyed. Of these participants, a large majority (77%) did not recognize a QR code, and 8% reported seeing such a code before, but did not know it could be scanned using a mobile phone app. Only 15% knew what the shown QR code was, and that it could be read using a QR code reader on a mobile phone. The awareness of QR codes by the general public could be considered rather low, and their utility in Swedish public settings is currently debatable

Spatial Implications of Minimum Wages

This paper addresses possible consequences of a minimum wage in a spatial context. An empirical analysis utilizing German data shows that a signifcant spatial wage structure exists and that, as a consequence, the share of workers earning wages below a minimum wage will be particularly high in rural counties even if we control for educational and occupational differences. A theoretical analysis discusses the implications for the spatial structure of the economy and shows that while the wages in the countryside will be affected positively, wages will decline in the city, where employment and population rise. Workers in the city will further suffer from an increase in housing costs. This supports concerns that urban poverty might increase as a result of the introduction of a minimum wage.Minimum Wages; Urban Poverty; Spatial Wage Structure; Mobility; Economies of Agglomeration