Langlebigkeit und Altern: Gene oder Umwelt?

Aging is defined as loss of homeostasis which affects all metabolic systems, including DNA. Interspecies comparisons and lessons from the human genetic instability syndromes suggest a correlation between DNA-homeostasis and maximum lifespan, whereas average lifespan depends mainly on environmental factors. Current demographic data suggest a maximum lifespan in humans of 110–115. The average life expectancy at birth has reached 80 years in the wealthy nations and may exceed, at least in females, 90 years by the year 2050. Genetic and biological reasons, but also lifestyle factors, account for the greater longevity of women. Attempt to define a ?longevity“ genotype so far have not been met with success, but carriers of the ApoE4-Allele appear to have a disadvantage. Unlike the situation in model organisms, aging and longevity in humans seem to be influenced by numerous genes and environmental interactions. Most people do not die of old age but of age-related diseases which are frequent because of lack of natural selection against genetic defects that cause late-onset diseases. Moreover, genes causing late-onset diseases show evidence of antagonistic pleiotropy, rendering these genes resistant to removal from our genome. Likewise, thermoinstability of DNA and generation of reactive oxygen species during oxidative phosphorylation are two endogenous sources of genomic instability that limit our lifespan and cannot be overcome without fundamentally altering the biological make-up of our species. Genomic instability causes cancer and accelerates the aging process, as evidenced by the human caretaker gene syndromes which typically show progeroid features. From a genetic point of view, cancer and aging may be moderately delayed and / or mitigated by lifestyle and medical / environmental interventions, but given the constraints of our biological make-up, they cannot be eradicated.     

Earnings management and initial public offerings: Evidence from the Netherlands

This paper presents one of the first studies of earnings management by initial public offering (IPO) firms in a European country. Using a sample of 64 Dutch IPOs, we investigate the pattern of discretionary current accruals (DCA) over time. We find that managers manage their company's earnings in the first year as a public company but not in the years before the IPO. We also examine the impact of earnings management on the long-run stock price performance of IPOs. We find a negative relation between the size of the DCA in the first year as a public company and long-run stock price performance over the next 3 years. A number of additional tests support these findings.     

The minimum variance hedge and the bankruptcy risk of the firm

In this paper, we analyze the influence of hedging with forward contracts on the firm's probability of bankruptcy (POB). The minimization of this probability can serve as a substitute for the maximization of shareholders' wealth. It is shown that the popular minimum variance hedge is generally neither necessary nor sufficient for the minimization of the firm's POB. Moreover, our model suggests a correction of the widespread view that a reduction in the variance of the future value of the firm is inevitably accompanied by a reduction in its default risk. We derive an analytical solution for the variance-minimizing hedge ratio of a firm exposed to both input and output price uncertainty that takes into account the issue of correlation. Based on this solution, we provide a graphical analysis to prove our claim that there is a fundamental difference between hedging policies focused on bankruptcy risk and those following conventional wisdom even if positive correlation constitutes a “natural” hedge.     

Term Structures in the Office Rental Market in Stockholm

This paper contains an empirical study of the rental term structure in a property market that included a dramatic boom and bust cycle. The study is applied to office leases in commercial properties located in Stockholm CBD, Sweden. The time period under study is 1977–1991. The number of observations (lease contracts) that we were able to make full use of in the regression analyses is n=861. For seven out of fifteen years studied, a significant term structure was observed. The estimated hedonic rent equation was also used to construct an office rental index.     

Migrants' Savings, Purchasing Power Parity, and the Optimal Duration of Migration

If some of the returns to migration accrue from returnmigration, the optimal duration of migration may be shorter thanthe feasible duration of migration. We develop a model that providesand highlights conditions under which return migration takesplace even though a reversal of the inter-country wage differentialdoes not occur. In particular, we consider the higher purchasingpower of savings (generated from work abroad) at home than abroadas a motive for return migration. Inter alia, our model producesa negative relationship between the optimal duration of migrationand the purchasing power differential and in some (but not all)cases, a negative relationship between the optimal duration ofmigration and the wage abroad. In addition, and contrary to ourprior anticipation, our utility maximization analysis suggeststhat East-West migration will tend to be temporary while inter-EuropeanCommunity (or intra-West European) migration will likely be permanent.     

Dortmunder Institut für Zeitungsforschung wird 80 Jahre alt / Gabriele Toepser-Ziegert leitet das Haus in die Zukunft

Ohne Zusammenfassung     

Voluntary disclosure and information asymmetry in Denmark

This paper examines if the level of voluntary disclosure affects information asymmetry for industrial companies listed on the Copenhagen Stock Exchange. Economic theory suggests that disclosing more information should lower the information asymmetry component of a firm's cost of capital [Leuz, C., & Verrecchia, R. E. (2000)]. The results indicate that voluntary disclosure is negatively associated with proxies for information asymmetry. The results are robust even after controlling for various firm characteristics introduced in related literature. Despite differences in institutional settings the findings in our paper are similar to the ones based on US data.     

Testing for Vertical Fiscal Externalities

The purpose of this paper is to design a test of whether the vertical external effects associated with tax base sharing among local and regional governments have become internalized via the intergovernmental transfer system. Such tests are important in the sense that the income tax rates chosen by different levels of government will generally be correlated, even if the resource allocation is optimal from society's point of view. By using panel data for the Swedish local and regional public sectors, the results imply that an increase in the regional income tax rate induces the municipalities in the region to decrease their income tax rates. In addition, we are able to reject the null hypothesis that the vertical external effects have become internalized.