Resonant forcing of nonlinear systems of differential equations

We study resonances of nonlinear systems of differential equations, including but not limited to the equations of motion of a particle moving in a potential. We use the calculus of variations to determine the minimal additive forcing function that induces a desired terminal response, such as an energy in the case of a physical system. We include the additional constraint that only select degrees of freedom be forced, corresponding to a very general class of problems in which not all of the degrees of freedom in an experimental system are accessible to forcing. We find that certain Lagrange multipliers take on a fundamental physical role as the effective forcing experienced by the degrees of freedom which are not forced directly. Furthermore, we find that the product of the displacement of nearby trajectories and the effective total forcing function is a conserved quantity. We demonstrate the efficacy of this methodology with several examples.Comment: 9 pages, 3 figure

Is there a trade-off between job security and wages in Germany and the UK?

This paper looks at the wage effects of perceived and objective insecurity in Germany and the UK using the GSOEP and BHPS panels. The distinction between perceived worry about job loss and economic indicators such as regional unemployment rates and the share of temporary contracts is established. The bargaining hypothesis that job security and wages are complements because of union bargaining power and preference is derived from a variant of the right to manage model. This hypothesis is contrasted with Rosen's theory of equalising differences where security and wages are substitutes. The empirical literature surveyed finds evidence for both sides. When addressing a number of econometric issues in earlier studies of the bargaining hypothesis this paper finds strong evidence in favour of the former. Accounting for simultaneous determination of job insecurity and wages significantly negative level effects are found for Germany with some evidence for those in the UK. There is also some evidence for growth rate effects (especially for perceived insecurity), but it does not appear robust. Job insecurity, both perceived and objective is found to have influenced wage development in both countries

Employment Adjustments on the Internal and External Labour Market: An Empirical Study with Personnel Records of a German Company

Firms are affected by the product demand. This leads to employment adjustments. In the literature we find only very few contributions investigating the issue whether internal adjustments are linked and which relationships exist with external adjustments. Are they of a complementary or substitutive nature? Furthermore, it is of interest to find out, whether we can observe an obvious trend and whether the adjustments are driven by cyclical movements. For this study we have an extensive data set of a large German manufacturing company, which supplies innovative products for the domestic and international market, provided on a monthly base from January 1999 to December 2005. The empirical analysis starts with descriptive statistics. We find that the employment adjustment cycle coincides only to a certain degree with the macroeconomic cycle. Internal and external adjustments are more characterized by complementarity than by substitution. Over the observed period we cannot detect analogous wage adjustments. It is noticeable that in 2003 compared with the years before the number of employees is substantially reduced. The econometric investigation is based on a two-stage approach. We start with a bivariate probit estimation in order to extract the relationship between the probability of overtime and of promotion. Unobserved variables have opposite effects on the former and the latter adjustment instrument. Furthermore, we detect a negative trend of internal employment adjustments. Cyclical effects are ambiguous. The next step, the determination of external adjustments with respect to overtime and promotion adjustments, is split into two estimates. On the one hand we do not distinguish between the type of external employment adjustment and on the other hand we use this information separating between quits, layoffs, workers with a cancellation agreement and with a transition into a transfer organisation. The first approach demonstrates that a promotion reduces the probability to leave the firm while overtime is positively associated with an external job change. This pattern holds generally speaking in the second, more detailed estimates. Quits are the exception. In this case we observe opposite effects. Finally, we cannot detect any influences of promotions on cancellation agreements. --Personnel records,overtime,promotion,job mobility,cancellation agreement,transfer organisation

Do Women Manage Smaller Funds?

Based on a sample of 467 asset managers from four countries we robustly find that women manage smaller funds than men, despite tough competition in this industry. Interestingly, the gender gap exists only for managers of smaller funds, i.e. at the lower end of the hierarchy, as quantile regressions show. This is inconsistent with the glass ceiling hypothesis. Going further, this gender gap is limited to large firms. Explanations may refer to large firms using market power in the area of smaller funds or to "visibility" among top asset managers protecting against unequal treatment of the sexes.segregation, asset managers, gender, attitudes, qualification

Allocation of infrastructural facilities

Problems of geographical distribution of infrastructural facilities in LDCs cannot be tackled without reference to development strategies. This should mainly be based on the answer to the question whether development ought to radiate from a given centre of growth, or whether a broader distribution over the whole territory is preferred

How does future tourism affect today's depletion of natural resources in a globalized world?

This paper sets up a two-period, two-sector trade model of a developing country which is abundant in a natural resource but scarce in industrial goods. It shows that lower future travel costs, rising demand for tourism and higher preferences for the environment slow down today's depletion of the non-renewable natural resource that can be used for consumption or for exporting tourism services. The benefits that accrue from sustainable resource use can be distributed over time such that the myopic developing country and forward-looking industrialized countries, which demand tourism services, are better off

The labor market effects of outsourcing parts and components: adverse Cournot competition

This paper contributes to Hübler (2008) who analyses a partial equilibrium model of outsourcing with Cournot competition in intermediate good production. Final production is located in Western Europe, whereas the intermediate good can be manufactured by a Western (outsourcing) or Eastern European supplier (offshore outsourcing). The paper asks the question how changes in production costs, in particular wages, affect output and thus labor input in the two regions. The paper proves analytically that under certain conditions higher production costs in one region reduce intermediate good production in both regions

Energy saving technology diffusion via FDI and trade: a CGE model of China

This paper introduces intra- and inter-sectoral technology diffusion via FDI and imports into a recursive-dynamic CGE model for climate policy analyses. It analyzes China's accession to a Post Kyoto emission regime that keeps global emissions from 2012 on constant. Due to ongoing energy efficiency gains, partly stemming from international technology diffusion, China will become a net seller of emission permits and steadily reduce emissions, possibly below their 2004 level until 2030. This will reduce the world CO2 price significantly. The impact of supporting foreign firms and of reducing import tariffs on Chinese welfare will not significantly change when China joins the Post Kyoto regime

Heritability of time preference: evidence from German twin data

Intergenerational correlations of time preference are well documented. However, there is still limited empirical evidence about the role of genetics in this transmission process. In our paper, we use data on roughly 3,000 twins from the German TwinLife project to estimate the heritability of time preference. We rely on an experimentally validated survey measure of temporal discounting, namely, self-assessed patience. The analysis of monozygotic and dizygotic twins enables us to apply standard biometric models. We find that genetic differences explain up to 23 percent of individual variation in patience. Whereas the additive genetic effect and common environmental effects are of minor importance, a major dominant genetic effect is present. These results indicate a notable degree of genetic influence on economic time preferences