Understanding Scientific Mobility: Characteristics, Location Decisions, and Knowledge Circulation. A Case Study of Internationally Mobile Austrian Scientists and Researchers

In today's knowledge-based global economy, highly qualified people acting as carriers of knowledge are playing a crucial role for the growth and development of organizations, cities and regions. Top-talent is regarded as the major source of innovation and competitive advantage, particularly in science and research. Highly skilled and educated workers, such as scientists and scholars, who are transferring their embodied knowledge from one place to another through geographical mobility, are referred to as knowledge spillover agents (KSA). Considering this context it is important to develop an understanding of the motivational dynamics, location factors and knowledge flows associated with mobility decisions of scientists and researchers. Based on qualitative data from in-depth interviews with Austrian scientists who are either currently staying abroad or have already returned this explorative study identifies some characteristics of scientific mobility, investigates the most relevant push and pull factors as well as sheds some light on the motivational dynamics at the individual level. acting as carriers of knowledge are playing a crucial role for the growth and development of organizations, cities and regions. Top-talent is regarded as the major source of innovation and competitive advantage, particularly in science and research. Highly skilled and educated workers, such as scientists and scholars, who are transferring their embodied knowledge from one place to another through geographical mobility, are referred to as knowledge spillover agents (KSA). Considering this context it is important to develop an understanding of the motivational dynamics, location factors and knowledge flows associated with mobility decisions of scientists and researchers. Based on qualitative data from in-depth interviews with Austrian scientists who are either currently staying abroad or have already returned this explorative study identifies some characteristics of scientific mobility, investigates the most relevant push and pull factors as well as sheds some light on the motivational dynamics at the individual level.growth/innovation

Error analysis for space and time discretizations of quasilinear wave-type equations

This thesis provides a unified framework for the error analysis for space and time discretizations of a quite general class of quasilinear wave-type problems. For the space discretization we prove a rigorous error estimate based on semigroup theory for nonautonomous problems. Compared to previous results, which are mostly based on Banach’s fixed-point theorem, this approach allows for a better insight into the individual error contributions. Furthermore, since wellposedness results for quasilinear wave-type problems are in general based on severe regularity assumptions with respect to the boundary of the domain, we consider nonconforming space discretizations in order to allow for domain approximation. Furthermore, we provide a rigorous error analysis for the full discretization with three different one-step time-integration schemes. On the one hand, we consider the implicit midpoint rule and a linearized version thereof. On the other hand, we also investigate the leapfrog scheme, which is an explicit scheme. Throughout this thesis, we illustrate the relevance of the abstract framework by application of our results to the undamped Westervelt equation and the Maxwell equations with Kerr nonlinearity. Finally, we conclude with numerical examples

Error analysis for full discretizations of quasilinear wave-type equations with two variants of the implicit midpoint rule

We study the full discretization of a general class of first- and second-order quasilinear wave-type problems with the implicit midpoint rule and a linearized variant thereof. Based on a proof by induction, we prove wellposedness and a rigorous error estimate for both schemes, combining energy techniques, inverse estimates, and a linearized fixed-point iteration for the analysis of the nonlinear scheme. To confirm the relevance of the general framework, we derive novel error esitmates for the full discretization of two prominent examples from nonlinear physics: the Westervelt equation and the Maxwell equations with Kerr nonlinearity

Knowledge Spillover Agents and Regional Development: Spatial Distribution and Mobility of Star Scientists

It is widely recognised that knowledge and highly skilled individuals as “carriers” of knowledge (i.e. knowledge spillover agents) play a key role in impelling the development and growth of cities and regions. In this paper we discuss in a conceptual way the relation between spatial movements of talent and knowledge flows and present empirical results on the geography and mobility patterns of star scientists. Our findings show that these phenomena a highly uneven in nature, benefiting only a few countries which are capable to act as magnet for scientific talent.DYNREG

Analytical and Numerical Analysis of Linear and Nonlinear Properties of an rf-SQUID Based Metasurface

We derive a model to describe the interaction of an rf-SQUID (radio frequency superconducting quantum interference device) based metasurface with free space electromagnetic waves. The electromagnetic fields are described on the base of Maxwell's equations. For the rf-SQUID metasurface we rely on an equivalent circuit model. After a detailed derivation, we show that the problem that is described by a system of coupled differential equations is wellposed and, therefore, has a unique solution. In the small amplitude limit, we provide analytical expressions for reflection, transmission, and absorption depending on the frequency. To investigate the nonlinear regime, we numerically solve the system of coupled differential equations using a finite element scheme with transparent boundary conditions and the Crank-Nicolson method. We also provide a rigorous error analysis that shows convergence of the scheme at the expected rates. The simulation results for the adiabatic increase of either the field's amplitude or its frequency show that the metasurface's response in the nonlinear interaction regime exhibits bistable behavior both in transmission and reflection.Comment: published in Physical Review B, Phys. Rev. B 99, 07540

Do hiring subsidies reduce unemployment among the elderly? Evidence from two natural experiments

We estimate the effects of hiring subsidies for older workers on transitions from unemployment to employment in Germany. Using a natural experiment, our first set of estimates is based on a legal change extending the group of eligible unemployed persons. A subsequent legal change in the opposite direction is used to validate these results. Our data cover the population of unemployed jobseekers in Germany and was specifically made available for our purposes from administrative data. Consistent support for an employment effect of hiring subsidies can only be found for women in East Germany. Concerning other population groups, firms´ hiring behavior is hardly influenced by the program and hiring subsidies mainly lead to deadweight effects. --Hiring subsidies,older workers,evaluation,natural experiments

Error analysis for space discretizations of quasilinear wave-type equations

In this paper we study space discretizations of a general class of first- and second-order quasilinear wave-type problems. We present a rigorous error analysis based on a combination of inverse estimates with semigroup theory for nonautonomous linear Cauchy problems. Moreover, we provide refined results for the special case that the nonlinearities are local in space. As applications of these general results we derive novel error estimates for two prominent examples from nonlinear physics: the Westervelt equation and the Maxwell equations with Kerr nonlinearity. We conclude with a numerical example to illustrate our theoretical findings

Numerical upscaling for wave equations with time-dependent multiscale coefficients

In this paper, we consider the classical wave equation with time-dependent, spatially multiscale coefficients. We propose a fully discrete computational multiscale method in the spirit of the localized orthogonal decomposition in space with a backward Euler scheme in time. We show optimal convergence rates in space and time beyond the assumptions of spatial periodicity or scale separation of the coefficients. Further, we propose an adaptive update strategy for the time-dependent multiscale basis. Numerical experiments illustrate the theoretical results and showcase the practicability of the adaptive update strategy