Unemployment and Employment Protection in a Unionized Economy with Search Frictions

Abstract. In the theoretical literature, the effects of employment protection on unemployment are ambiguous. Higher employment protection reduces job creation as well as job destruction. However, in most models, wages are bargained individually between workers and firms. Using a conventional matching model in which a monopoly union sets wages, I show that employment protection can unambiguously increase unemployment. Interestingly, I find that tightening the restrictions on redundancies and dismissals may even increase the probability of dismissal.     

Efficient design of experiments in the Monod model

Summary. Estimation and experimental design in a non-linear regression model that is used in microbiology are studied. The Monod model is defined implicitly by a differential equation and has numerous applications in microbial growth kinetics, water research, pharmacokinetics and plant physiology. It is proved that least squares estimates are asymptotically unbiased and normally distributed. The asymptotic covariance matrix of the estimator is the basis for the construction of efficient designs of experiments. In particular locally D -, E - and c -optimal designs are determined and their properties are studied theoretically and by simulation. If certain intervals for the non-linear parameters can be specified, locally optimal designs can be constructed which are robust with respect to a misspecification of the initial parameters and which allow efficient parameter estimation. Parameter variances can be decreased by a factor of 2 by simply sampling at optimal times during the experiment.     

The application of graph theory and percolation analysis for assessing change in the spatial configuration of pond networks

Urban Ecosystems - Pond networks support high levels of biodiversity when compared to other freshwater ecosystems such as rivers, lakes and streams. The persistence of species in these small,...     

Nuptiality in the Course of the Demographic Transition: The Experience of the Balkan Countries

The paper examines marriage patterns in four Balkan countries during the course of the demographic transition. It is shown by analysis of the available data that cultural and institutional factors, such as family type, kinship structure or religious doctrines, alone, cannot explain adequately all the features of nuptiality in the region. Without denying the importance of the ‘cultural-institutional’ approach, it was found necessary to expand it by taking into account the distinctive historical and developmental context in a given country or region. It is argued that the relative importance of marriage postponement (and celibacy), birth control, and out-migration, as parts of a complex system of ‘adjustments’ to sustained population growth, was determined by the rate of this growth, as well as by the pace of socio-economic development and a number of other factors (including institutional and cultural ones). The experience of the Balkan countries is explored with this assumption as a background.     

Transformation and Anomie: Problems of Quality of Life in Bulgaria

The weakening of social integration and anomie are unavoidable in the transformation of societies. The effect is a decrease of quality of life accompanied by disenchantments, aggressiveness and escapism. In some countries in Eastern Europe like Bulgaria the anomie effects of transformation became particularly strong. The major reason is the political instability. The dissolution of the previous state-centered over-integration of society developed into a dissolution of major mechanisms of political integration. The prospects for improvement of quality of life are focused on the balance of economic, political and cultural re-integration of Bulgarian society.     

Correction of Density Estimators that are not Densities

Abstract. Several old and new density estimators may have good theoretical performance, but are hampered by not being bona fide densities; they may be negative in certain regions or may not integrate to 1. One can therefore not simulate from them, for example. This paper develops general modification methods that turn any density estimator into one which is a bona fide density, and which is always better in performance under one set of conditions and arbitrarily close in performance under a complementary set of conditions. This improvement-for-free procedure can, in particular, be applied for higher-order kernel estimators, classes of modern h ⁴ bias kernel type estimators, superkernel estimators, the sinc kernel estimator, the k -NN estimator, orthogonal expansion estimators, and for various recently developed semi-parametric density estimators.