Stochastic Analysis of Intermediate Lesions in Carcinogenesis Experiments

In many animal model systems for carcinogenesis, well characterized putative premalignant lesions are observed. A much studied example is provided by the enzyme altered foci in rodent hepatocarcinogenesis experiments. In a recent paper, we proposed a method for the quantitative analysis of such premalignant lesions. The model used in that paper assumed that the mean growth of premalignant clones is exponential. However, it has been suggested that such a model is oversimplified. In this paper, we relax the assumption of exponential mean growth. The new model contains one extra parameter that measures departures from exponentiality. Use of the model is illustrated by analysis of ATPase deficient foci in the liver of rats given NNM (N-nitrosomorpholine) in their drinking water. The analysis suggests that the clonal growth of altered cells is significantly accelerated (superexponential) for nontoxic doses of NNM. Finally, the hazard function of the two-mutation model for carcinogenesis is briefly discussed under nonexponential (mean) growth of intermediate cells.     

Distance Testing for Selecting the Best Population

Consider testing the null hypothesis that a given population has location parameter greater than or equal to the largest location parameter of k competing populations. This paper generalizes tests proposed by Gupta and Bartholomew by considering tests based on p -distances from the parameter estimate to the null parameter space. It is shown that all tests are equivalent when k →∞ for a class of distributions that includes the normal and the uniform. The paper proposes the use of adaptive quantiles. Under suitable assumptions the resulting tests are asymptotically equivalent to the uniformly most powerful test for the case that the location parameters of all but one of the populations are known. The increase in power obtained by using adaptive tests is confirmed by a simulation study.     

Welfare Attitudes and Social Expenditure: Do Regimes Shape Public Opinion?

This article examines the link between regime types, social expenditure, and welfare attitudes. By employing data on 19 countries taken from the World Values Survey, the main aim is to see to what degree the institutions of a country affect the attitudes of its citizens. According to Esping-Andersen (The three worlds of welfare capitalism. Polity Press, Cambridge, 1990) welfare regimes can be classified into Liberal, Conservative, and Social Democratic categories. With this as my point of departure, I put forward two research questions: the first concerns the direct influence of regime type on people’s attitudes; the second seeks to trace the contours of the regime types by arguing that both social expenditure and welfare attitudes are products of a country’s institutional arrangements. These questions are answered through regression modelling and by examining the interplay between welfare attitudes, social expenditure, and welfare regimes. First, we see that there are significant differences in aggregated attitudes between countries belonging to the Liberal and the Conservative regimes, with the former’s citizens holding more rightist views than those of the latter. This is explained by the history and organization of welfare benefits of the two variations of Esping-Andersen’s classification. Second, by graphing welfare attitudes against social expenditure the outline of the three regime types mentioned above may be seen. Similar correspondence is not found with regards to an Eastern European category. All in all, this study renders some support for the regime argument.     

On the Use of Social Clocks for the Monitoring of Multidimensional Social Development

This article describes a new methodology for monitoring multidimensional social development using social clocks: comparisons with so called reference trajectories make it possible to establish the development stage of a country along a number of independent time axes, thus affording new opportunities for analyzing leads, lags, and asynchronies between variables and countries. This article explores these new possibilities and discusses some of the difficulties in the use of social clocks. To demonstrate the fruitfulness of the new concepts, the article presents an application of the methodology by analyzing the socio-economic development of ten Eastern European countries in the period before they joined the European Union.     

Risk, complexity, and deviations from expected-value maximization: Results of a lottery choice experiment

Varying several parameters of single-stage lottery choice tasks we investigate the question which features of a decision task lead subjects to deviate from maximizing expected monetary value (EV). Despite small differences in EV between the two lotteries in the choice sets, the subjects on average chose the lottery with the higher EV in every task. Risk avoidance occurs, but not consistently over all tasks. Further results are that subjects prefer less complex lotteries over more complex ones, and that risk matters the more the less complex the decision task is.     

Are real options more valuable in the presence of agency conflicts?

The theory on real options has extended the traditional net present value rule in order to capture the value of flexibility in investment decisions. Typically, the theory of real options does not take into account agency conflicts (between central and divisional management). In this paper, we investigate the influence of agency conflicts on real options within a LEN-type model. We extend a standard LEN model with investment activities by explicitly considering the possibility to abandon an investment project after all parties involved have received further information about the project’s development. Especially, we analyze how the option’s flexibility value is influenced by the agency conflict. Our analysis shows that the real option alters the trade-off between risk sharing and incentives that underlies the agency conflict. Thereby, situations can occur in which central (and divisional) management evaluates the abandonment option ex ante differently than ex post. Using this framework, we discuss the role of commitment and the advantages of centralization and delegation of the abandonment decision.

Facts,Opinions, and Scientific Memes: Reflections of and Recommendations for the March for Science in Germany

Germany ranked second in number of March for Science participants. The current essay is based on a focus group discussion with six participants of a march in a German university town and elucidates their motives for attending, their perceptions of how politically active scientists should be, the goals they think the march should aim to achieve, and their recommendations for future marches. Motives in Germany differed slightly from those mentioned in the United States. Discussants placed importance on the difference between facts and opinions, which is translated into recommendations for issue‐specific future marches.