AIDS-Hilfe in Afrika

Tansanische Krankenschwestern im mobilen Einsatz — Tansania ist eines der ?rmsten L?nder der Erde. Und nur in drei L?ndern weltweit gibt es mehr HIV-Infizierte. Mit internationaler Hilfe werden in vielen Regionen Versorgungsprojekte initiiert und Therapiezentren gegründet. Seit 2007 gibt es au?erdem ein nationales HIV-Programm. Dadurch gelingt es, das Tabu um HIV langsam aufzubrechen. Doch der Weg zur Eind?mmung der Epidemie ist mühsam.     

Using vignettes to study family consumption processes

The use of vignettes for qualitative consumer research is discussed in this article. More specifically, vignettes are proposed as a useful research technique for conducting systematic and rigorous studies of consumer interaction processes, in particular as these relate to family consumption issues. Following an overview of methodological and practical problems of studying consumption interaction processes in families, a discussion of how vignettes may be used to enhance knowledge of family decision‐making processes in real‐life contexts is presented. Design implications are discussed and strategies for applying the vignette method are outlined and illustrated by two recent studies of pro‐environmental consumer behavior in a family context. The paper concludes with a discussion of the benefits and the possible pitfalls of using vignettes. © 2010 Wiley Periodicals, Inc.     

Climate Change Mitigation with Technology Spillovers

We explore the implications of an increase in clean technology spillovers between developed and developing countries. We build a game of abatements in which players are linked with technology spillovers determined by an initial choice of absorptive capacities by developing countries. We show that, within a non-cooperative framework, the response of clean technology investments in developed countries to an increase in cross-country technology spillovers is ambiguous. If the marginal benefits of these additional abatements are not sufficiently high, developed countries have a strategic incentive to decrease investments. Such a strategic response jeopardizes the initial effects of an increase in technology spillovers on climate change mitigation and decreases the incentives for developing countries to enhance their absorptive capacities.     

When less conditioning provides better estimates: overcontrol and endogenous selection biases in research on intergenerational mobility

Quality & Quantity - The counterfactual approach to causality has become the dominant approach to understand causality in contemporary social science research. Whilst most sociologists are...     

An application of the renewal theoretic selection principle: The first divisible sum

Summary This paper deals with the distribution of the first partial sum of a sequence of independent and identically distributed random variables which is divisible by some integerk>1. We give a formula for its characteristic function and obtain limit results fork. A new characterization of the geometric distribution is also given. The results are applicable to models such as periodically observed self-renewing aggregates.     

Einzelbesprechungen

Ohne Zusammenfassung     

Family size and child outcomes: Is there really no trade-off?

We study the impact of family size on intermediate and long-term outcomes using twin births as an exogenous source of variation in family size in an unusually rich dataset. Similar to recent studies, we find no evidence of a causal effect on long-term outcomes and show that not taking selection effects into account will likely overstate the effects. We do, however, find a small but significant negative impact of family size on grades in compulsory and secondary school among children who are likely to be vulnerable to further restrictions on parental investments.     

Model uncertainty and aggregated default probabilities: new evidence from Austria

Understanding the determinants of aggregated corporate default probabilities (PDs) has attracted substantial research interest over the past decades. This study addresses two major difficulties in understanding the determinants of aggregate PDs: model uncertainty and multicollinearity among the regressors. We present Bayesian model averaging (BMA) as a powerful tool that overcomes model uncertainty. Furthermore, we supplement BMA with ridge regression to mitigate multicollinearity. We apply our approach to an Austrian data set. Our findings suggest that factor prices like short-term interest rates (STIs) and energy prices constitute major drivers of default rates, while firms’ profits reduce the expected number of failures. Finally, we show that the results of our model are fairly robust with respect to the choice of the BMA parameters.     

An evolutionary explanation of the value premium puzzle

As early as 1934 Graham and Dodd conjectured that excess returns from value investment originate from a tendency of stock prices to converge towards a fundamental value. This paper confirms their insights within the evolutionary finance model of Evstigneev et al. (Econ Theory 27:449–468, (Evstigneev et al. 2006)). Our empirical results show the predictive power of the evolutionary benchmark valuation for the relative market capitalization and its dynamics in the sample of firms listed in the Dow Jones Industrial Average index in 1981–2009.