Heavy Flavour Electroweak Physics Review

The four LEP experiments and the SLD detector have measured the Z partial widths for Z decays into b and c quarks and the corresponding forward-backward asymmetries at centre-of-mass energies close to the Z boson mass. The results yield a very precise determination of the effective vector and axial-vector coupling constants and of the underlying electroweak mixing angle sin(theta[eff,lep]), probing the Standard Model prediction for the electroweak radiative corrections. Of special interest is hereby a difference at the level of three standard deviations in the mixing angle results from lepton production and those obtained from the forward-backward asymmetry in b quark production. The b quark asymmetry measurements, some of which are still in the process of being finalised, are therefore discussed in detail.Comment: 6 pages, 8 figures, to be published in the proceedings of: XXXVIII-th Rencontres de Moriond: Electroweak Interactions and Unified Theorie

Detectability of extrasolar moons as gravitational microlenses

We evaluate gravitational lensing as a technique for the detection of extrasolar moons. Since 2004 gravitational microlensing has been successfully applied as a detection method for extrasolar planets. In principle, the method is sensitive to masses as low as an Earth mass or even a fraction of it. Hence it seems natural to investigate the microlensing effects of moons around extrasolar planets. We explore the simplest conceivable triple lens system, containing one star, one planet and one moon. From a microlensing point of view, this system can be modelled as a particular triple with hierarchical mass ratios very different from unity. Since the moon orbits the planet, the planet-moon separation will be small compared to the distance between planet and star. Such a configuration can lead to a complex interference of caustics. We present detectability and detection limits by comparing triple-lens light curves to best-fit binary light curves as caused by a double-lens system consisting of host star and planet -- without moon. We simulate magnification patterns covering a range of mass and separation values using the inverse ray shooting technique. These patterns are processed by analysing a large number of light curves and fitting a binary case to each of them. A chi-squared criterion is used to quantify the detectability of the moon in a number of selected triple-lens scenarios. The results of our simulations indicate that it is feasible to discover extrasolar moons via gravitational microlensing through frequent and highly precise monitoring of anomalous Galactic microlensing events with dwarf source stars.Comment: 14 pages, 11 figures. Updated to A&A published version: updated references, 1 additional illustration (Fig. 10), further analogies to solar system and extended discussio

Organizational Data

Organizational data describe central characteristics of organizations, their internal structures and processes as well as their behavior as corporate actors in different social and economic contexts. Firm and enterprise data are the most frequently used type of organizational data, but there is also a growing interest in data on schools, universities, and hospitals in the economic and social science research. In the last several years, there has been a substantial improvement in the accessibility and scientific usability of organizational data from official statistics. However, nonofficial organizational data produced within publicly funded research projects are practically impossible to obtain for secondary analyses. There is no documentation of the existing stock of non-official organizational data, and the methodological standards used for organizational research in Germany are low compared to the standards of international research. Against this background, it is recommended that efforts be focused on documenting and archiving the existing non-official organizational data for secondary analyses and on establishing higher methodological standards within this research field.firms, organizations, methods of organizational research, micro data, secondary analysis

Identifying Influential Nodes in Bipartite Networks Using the Clustering Coefficient

The identification of influential nodes in complex network can be very challenging. If the network has a community structure, centrality measures may fail to identify the complete set of influential nodes, as the hubs and other central nodes of the network may lie inside only one community. Here we define a bipartite clustering coefficient that, by taking differently structured clusters into account, can find important nodes across communities

Predicting Item Popularity: Analysing Local Clustering Behaviour of Users

Predicting the popularity of items in rating networks is an interesting but challenging problem. This is especially so when an item has first appeared and has received very few ratings. In this paper, we propose a novel approach to predicting the future popularity of new items in rating networks, defining a new bipartite clustering coefficient to predict the popularity of movies and stories in the MovieLens and Digg networks respectively. We show that the clustering behaviour of the first user who rates a new item gives insight into the future popularity of that item. Our method predicts, with a success rate of over 65% for the MovieLens network and over 50% for the Digg network, the future popularity of an item. This is a major improvement on current results.Comment: 25 pages, 11 figure

Unjust Divergence in Earnings in Germany?

Since a court decided that bonuses paid to the former top management at Mannesmann AG were unjustifiable there has been widespread public discussion over fair pay in Germany. This has been against the background of big increases in the salaries paid to top executives at a time when the economy is sluggish and there is high unemployment. A special survey by the Socio-Economic Panel (SOEP) conducted by DIW Berlin in conjunction with Infratest Sozialforschung showed that many people feel top executives are too highly paid, and that the differences between their earnings and those of unskilled workers is not justifiable. Many, especially in eastern Germany, also feel that their own pay is unfairly low. Greater transparency would increase the acceptance of differentials that are otherwise seen as unjust.

How does income inequality influence international migration?

The increasing importance of highly-skilled migration in times of so-called ?skills shortages? is leading to a growing interest in the determinants and characteristics of highly-skilled migration. However, migration theory with regard to the highly-skilled is not well developed. An important strand of literature that clearly serves for the derivation of empirically testable hypotheses about the determinants of particular types of migrants is self-selection theory. This theory dates back to Roy (1951) and has been adopted by Borjas (1987) for the analysis of the relation between the income distribution and the skills of migrants. He concludes that a relatively more equal income distribution in the host country vis-à-vis the source country leads to a negative self-selection of migrants (i.e. the lowly-skilled will be particularly attracted) and vice versa. Borjas has confirmed this hypothesis with data on immigration to the US. Chiswick (1999) and others, however, have questioned these results. Sample-selection biases may arise in single-country analyses and in all studies based on host-country data, due to the impact of host-country specifics such as migration policy, network migration, and the like. Due to a lack of internationally comparable data, however, international empirical studies with data from the origin countries have not been undertaken to resolve the dispute between Borjas and Chiswick. Furthermore, data on the intentions to emigrate (as opposed to actual migration data) has the distinct advantage of being free from the above-mentioned selection-bias problem. This paper sheds some new light on the self-selection controversy by analysing the relationship between country-specific emigration propensities and each country?s score on the Gini-Index on inequality. The 1995 International Social Survey Programme (ISSP) conducted a survey on national identity, which gathers the necessary data in a rich international microdata set. We run probit-regressions with two samples, one including all surveyed persons and one including only the sub-sample of the highly-skilled. By relying on the Gini index as a proxy for wage inequality, the paper follows Borjas? (1987) approach. Borjas, however, proxies skills differentials by income differentials. Chiswick (1999) argues that these two differentials may only be poorly related. The analysis presented here partly avoids this criticism, as we compare the sub-sample of highly-skilled persons with all surveyed individuals and with the medium- and lowly-skilled. A strong positive correlation between skills and income, as predicted by standard economic theory, therefore suffices for the validity of our approach. The main result of this paper is that, ceteris paribus, a more egalitarian income distribution is associated with lower emigration propensities, while income inequality does not have any impact on the emigration propensities of particularly highly-skilled persons. These results seem to contradict Borjas? prediction that the highly-skilled should be particularly attracted by countries which have relatively high returns to skills. Thus, our analysis is more in line with the arguments put forward by Chiswick (1999) and others.

Perceived Income Justice Depends on the Economy

At least half of all employees in Germany described their wages in all three survey years under consideration here - 2005, 2007, and 2009 - as just. Still, major changes occurred over this period in how people perceived their earnings. Data from the Socio- Economic Panel (SOEP) Study show that after an increase in income dissatisfaction in 2007, the percentage of the population who consider their income unjust has again decreased substantially in 2009 - at 30 percent - to 2005 levels. This suggests that in times of economic crisis, people are willing to lower their earnings expectations, while in times of economic growth - like the year 2007 - they expect to share in the benefits of increased prosperity. The analysis shows that it was mainly people in the low to medium income range and in particular skilled workers who perceived their net income as unjust, a perception that remained stable over time. This is partly due to the income taxes paid by these groups. In the upper income segment, in contrast, no negative effect of the income tax burden on perceived income justice is found. Finally, the results confirm previous studies indicating that even in a world in which everyone received the wages they subjectively perceived to be fair, income differences between men and women would still persist. Women's income expectations are significantly lower than men's - even within the individual occupational groups.Justice, SOEP, Inequality