Gut geruht?

Schlafst?rungen vorbeugen - Oft sind Schlafst?rungen Bestandteil psychischer, organischer oder neurologisch degenerativer Erkrankungen. Sie k?nnen aber auch die Folge falschen Verhaltens oder ungemessener Schlafbedingungen sein. Also: Was f?rdert gesunden Schlaf, was behindert ihn?     

The optimal selective logging regime and the Faustmann formula

This study analyzes the optimal selective logging regime of a size-distributed forest where individual trees compete for scarce resources such as space, light, and nutrients. The decision problem of the forest manager is formulated as a distributed optimal control problem. The interpretation of the first-order conditions allows a generalization of the Faustmann formula. In an empirical part, this article numerically determines the optimal management regime of a size-structured forest and shows that the optimal selective logging regime is associated with a normal forest under a wider variety of situations than stated in the previous literature.     

Distributions slanted to the right

We solve Problem 234 in Statistica Neerlandica by introducing the concept of slantedness. Distributions with a decreasing Lebesgue density are slanted to the right. This is no longer true for distributions on a lattice with decreasing density. Both kinds of distributions have positive central odd moments.     

SHORT-AND LONG-RUN FARM PLANNING UNDER UNCERTAINTY; INTEGRATION OF LINEAR PROGRAMMING AND DECISION TREE ANALYSIS

The paper presents an approach to an integrated long-run and short-run farm planning under uncertainty, based on a decomposition of the problem into (i) a series of short-run plans, and (ii) a master long-run plan. The series of the short-run plans are parametrically solved by linear programming "variable right hand" techniques and are later integrated into a long-run program using a (computerized) decision tree analysis. The attitude towards risk of the farm operator is expressed in the willingness to maximize the expected value of the income stream over the planning horizon subject to the restriction that alternatives which may lead to lack of liquidity must be eliminated.
Ce travail présenle une approche tentative ďintégrer, sous conditions incertaines, une planification de ferme à court et long terme. La planification est basée sur la partition du problème en (i) série de courte durée et (ii) de tongue durée. Les séries de courte durée sont résolues àľaide dun programme linéaire, et intégreés ensuite dans un programme à long terme àľaide de ľanalyse de "décision arbre."ľattitude envers les risques de ľentrepreneur est exprimée par la volonté-de maxiliser la valeur de revenu prévu au delá de la planification sous resérve de la restriction que des alternatives qui peuvent conduire à un manque de moyens liquides, doivent être éliminees.     

The (ir)relevance of real wage rigidity in the New Keynesian model with search frictions

We develop a New Keynesian model with search and matching frictions in the labor market. We show that the model generates counterfactual labor market dynamics. In particular, it fails to generate the negative correlation between vacancies and unemployment in the data, i.e., the Beveridge curve. Introducing real wage rigidity leads to a negative correlation, and increases the magnitude of labor market flows to more realistic values. However, inflation dynamics are only weakly affected by real wage rigidity. The reason is that labor market frictions give rise to long-run employment relationships. The measure of real marginal costs that is relevant for inflation in the Phillips curve contains a present value component that varies independently of the real wage.     

Why do rich countries prefer free trade over free migration? The role of the modern welfare state

"According to traditional trade theory (Heckscher-Ohlin), free trade and free migration are equivalent measures of economic integration leading both to an equalization of factor prices. This prediction is in sharp opposition to the observed preference of rich countries for free trade over free migration. We provide an explanation for this inconsistency: the redistribution policies in the countries. Social welfare in countries with a relatively small number of low-skilled native workers is higher with free trade than with free migration due to redistribution of income towards immigrating workers."     

Cost-utility analysis of the rehabilitation of patients with musculoskeletal problems

The objective of this study is to discuss the rehabilitation of patients in primary health care with problems in the musculoskeletal system from a socioeconomic perspective. A trial with coordinated rehabilitation in primary health care is compared with traditional rehabilitation. This trial, performed in Sweden in 1994, was a two-year prospective and comparative study of consecutively included patients with long-term illnesses due musculoskeletal problems (810 observations). A cost-utility analysis shows that the new rehabilitation program in primary health care is a cost-minimization program for society. There is no significant difference in the quality of life between the trial and control groups. The total cost is lower for rehabilitation in primary health care than for traditional rehabilitation (6 percent). The indirect costs are higher than the direct health care costs (60 percent), and payments from social insurance increased by 8 percent. The health economic results support rehabilitation in primary health care but also points out that this type of rehabilitation can be further improved.