International migration with heterogeneous agents : theory and evidence

"Two puzzling facts of international migration are that only a small share of a sending country's population emigrates and that net migration rates tend to cease over time. This paper addresses these issues in a migration model with heterogeneous agents that features temporary migration. In equilibrium a positive relation exists between the stock of migrants and the income differential, while the net migration flow becomes zero. Consequently, empirical migration models, estimating net migration flows instead of stocks, may be misspecified. This suspicion appears to be confirmed by our empirical investigation of cointegration relationships of flow and stock migration models." (Author's abstract, IAB-Doku) ((en))Herkunftsland, internationale Wanderung - Modell, Wanderungspotenzial, Wanderungsstatistik, Mobilitätsbereitschaft - Determinanten, regionale Mobilität, Einkommensunterschied, Einwanderungsland, Rückwanderung, Rückwanderungsbereitschaft, Aufenthaltsdauer, Migrationstheorie, Stromgrößenanalyse, ökonomische Faktoren, Wanderungsmotivation, Mobilitätsforschung, Europäische Union, Welt

Numerical thermo-elasto-plastic analysis of residual stresses on different scales during cooling of hot forming parts

In current research, more and more attention is paid to the understanding of residual stress states as well as the application of targeted residual stresses to extend e.g. life time or stiffness of a part. In course of that, the numerical simulation and analysis of the forming process of components, which goes along with the evolution of residual stresses, play an important role. In this contribution, we focus on the residual stresses arising from the austenite-to-martensite transformation at microscopic and mesoscopic level of a Cr-alloyed steel. A combination of a Multi-Phase-Field model and a two-scale Finite Element simulation is utilized for numerical analysis. A first microscopic simulation considers the lattice change, such that the results can be homogenized and applied on the mesoscale. Based on this result, a polycrystal consisting of a certain number of austenitic grains is built and the phase transformation from austenite to martensite is described with respect to the mesoscale. Afterwards, in a two-scale Finite Element simulation the plastic effects are considered and resulting residual stress states are computed

Corrective Ad Valorem and Unit Taxes: A Welfare Comparison

The ad valorem versus unit taxes debate has traditionally emphasized tax yield. For this criterion, ad valorem taxes outperform unit taxes in terms of welfare for a wide range of imperfect competition settings, including Dixit-Stiglitz monopolistic competition. Yet, in a number of policy fields, such as environmental, health or trade economics, policy makers apply taxes to target the production/consumption volume in an industry, i.e. aim at a certain corrective effect rather than tax yield. This paper compares the two tax instruments with respect to equal corrective-effect in a Dixit-Stiglitz setting with love of variety, entry, exit, and redistribution of tax revenues. We find that unit taxes lead to more firms in the industry, less output per firm, less tax revenue, but higher welfare compared to ad valorem taxes.Externalities; Monopolistic competition; Taxes; Specific taxes; Welfare

How to Turn an Industry Green: Taxes versus Subsidies

Environmental policies frequently target the ratio of dirty to green output within the same industry. To achieve such targets the green sector may be subsidised or the dirty sector be taxed. This paper shows that in a monopolistic competition setting the two policy instruments have different welfare effects. For a strong green policy (a severe reduction of the dirty sector) a tax is the dominant instrument. For moderate policy targets, a subsidy will be superior (inferior) if the initial situation features a large (small) share of dirty output. These findings have implications for policies such as the Californian Zero Emission Bill or the EU Action Plan for Renewable Energy Sources.Environmental policy; Monopolistic competition; Taxes; Subsidies; Welfare; Zero Emission Bill

Bug-Fixing and Code-Writing: The Private Provision of Open Source Software

Open source software (OSS) is a public good. A self-interested individual would consider providing such software, if the benefits he gained from having it justified the cost of programming. Nevertheless each agent is tempted to free ride and wait for others to develop the software instead. This problem is modelled as a war of attrition with complete information, job signaling, repeated contribution to the public good and uncertainty in programming. The resulting game does not feature any delay: software will be provided swiftly, by young, low-cost individuals who gain considerably by signaling their programming skills; the startup (and collapse) of an OSS project displays bandwagon dynamics.open source software, war of attrition, public goods

Segment selection by relationship strength

Relationship management is becoming more important, also in direct marketing. Measuring the strength of relationships is relevant, since relationship strength can be used as a segmentation variable. However, in measuring relationship strength, mostly one or more behavioral indicators are used (e.g. the R/F/M-formula). So, these indicators measure customer quality instead of relationship quality, which is mainly determined by customer perceptions. This paper shows some preliminary results of a relationship audit, which depends on customer attitudes towards the relationship.marketing ;