5,298 research outputs found
Human Capital and Wages in Exporting Firms
This paper studies the link between a firms education level, export performance and wages of its workers. We argue that firms may escape intense competition in international markets by using high skilled workers to differentiate their products. This story is consistent with our empirical results. Using a very rich matched worker-firm longitudinal dataset we find that firms with high export intensities pay higher wages. However, an interaction term between export intensity and skill intensity has a positive impact on wages and it absorbs the direct effect of the export intensity. That is, we find an export wage premium, but it accrues to workers in firms with high skill intensities.exports; wages; human capital; rent sharing; matched worker- firm data
Computational modelling of diffusion magnetic resonance imaging based on cardiac histology
The exact relationship between changes in myocardial microstructure as a result of heart disease and the signal measured using diffusion tensor cardiovascular magnetic resonance (DT-CMR) is currently not well understood. Computational modelling of diffusion in combination with realistic numerical phantoms offers the unique opportunity to study effects of pathologies or the efficacy of improvements to acquisition protocols in a controlled in-silico environment. In this work, Monte Carlo random walk (MCRW) methods are used to simulate diffusion in a histology-based 3D model of the myocardium. Sensitivity of typical DT-CMR sequences to changes in tissue properties is assessed.
First, myocardial tissue is analysed to identify important geometric features and diffusion parameters. A two-compartment model is considered where intra-cellular compartments with a reduced bulk diffusion coefficient are separated from extra-cellular space by permeable membranes. Secondary structures like groups of cardiomyocyte (sheetlets) must also be included, and different methods are developed to automatically generate realistic histology-based substrates. Next, in-silico simulation of DT-CMR is reviewed and a tool to generate idealised versions of common pulse sequences is discussed. An efficient GPU-based numerical scheme for obtaining a continuum solution to the Bloch--Torrey equations is presented and applied to domains directly extracted from histology images. In order to verify the numerical methods used throughout this work, an analytical solution to the diffusion equation in 1D is described. It relies on spectral analysis of the diffusion operator and requires that all roots of a complex transcendental equation are found. To facilitate a fast and reliable solution, a novel root finding algorithm based on Chebyshev polynomial interpolation is proposed. To simulate realistic 3D geometries MCRW methods are employed. A parallel simulator for both grid-based and surface mesh--based geometries is presented. The presence of permeable membranes requires special treatment. For this, a commonly used transit model is analysed. Finally, the methods above are applied to study the effect of various model and sequence parameters on DT-CMR results. Simulations with impermeable membranes reveal sequence-specific sensitivity to extra-cellular volume fraction and diffusion coefficients. By including membrane permeability, DT-CMR results further approach values expected in vivo.Open Acces
Do Foreign Experts Increase the Productivity of Domestic Firms?
While most countries welcome (and some even subsidise) high-skilled immigrants, there is very limited evidence of their importance for domestic firms. To guide our empirical analysis, we first set up a simple theoretical model to show how foreign experts may impact on the productivity and wages of domestic firms. Using matched worker-firm data from Denmark and a difference-indifferences matching approach, we then find that firms that hire foreign experts – defined as employees eligible for reduced taxation under the Danish "Tax scheme for foreign researchers and key employees" – both become more productive (pay higher wages) and increase their exports of goods and services.foreign experts, export, immigrants, productivity, difference-in-differences matching
Do Immigrants Take the Jobs of Native Workers?
In this paper, we focus on the short-run adjustments taking place at the workplace level when immigrants are employed. Specifically, we analyse whether individual native workers are replaced or displaced by the employment of immigrants within the same narrowly defined occupations at the workplace. For this purpose, we estimate a competing risks duration model for job spells of native workers that distinguishes between job-to-job and job-to-unemployment transitions. In general, we do not find any signs of native workers being displaced by immigrants. Furthermore, we find only very limited signs of replacement of native workers by immigrants. Instead, in particular low-skilled native workers are less likely to lose or leave their jobs when the firms hire immigrants.immigration, adjustment costs, displacement, job spells, duration model
Skill Upgrading and Rigid Relative Wages: The Case of Danish Manufacturing
Relative wages have been remarkably rigid for the last two decades in Danish manufacturing despite large shifts in relative employment from unskilled labor towards skilled and educated labor. Assuming capital-skill complementarity and fixed relative wages as a consequence of labor market institutions, we argue that skill upgrading is more pronounced during downturns than upturns. This prediction is supported by a high positive and significant correlation
between changes in relative employment of skilled labor and changes in the unemployment rate. Furthermore, we show that international outsourcing has played an important role in explaining the shift in relative labor demand
Covariant Helicity-Coupling Amplitudes: A New Formulation
We have worked out covariant amplitudes for any two-body decay of a resonance
with an arbitrary non-zero mass, which involves arbitrary integer spins in the
initial and the final states. One key new ingredient for this work is the
application of the total intrinsic spin operator which is given
directly in terms of the generators of the Poincar\'e group.
Using the results of this study, we show how to explore the Lorentz factors
which appear naturally, if the momentum-space wave functions are used to form
the covariant decay amplitudes. We have devised a method of constructing our
covariant decay amplitudes, such that they lead to the Zemach amplitudes when
the Lorentz factors are set one
Skill-biased technological change in Denmark : a disaggregate perspective
In this paper, we provide an industry-level analysis of skill-biased technological change (SBTC) in Denmark over the last two decades. The analysis shows that SBTC has varied considerably across industries, and traditionally large Danish industries have experienced relatively less SBTC. This may partly explain why wage inequality between skilled and less skilled has risen less in Denmark than in other countries. We also find that SBTC has been concentrated in already skill-intensive industries. This contains important information about
future labour requirements, as the relative importance of these industries must be expected to grow, thereby reinforcing the shift in demand for skilled labour
Promoting transportation cycling for women: The role of bicycle infrastructure
Objective. Females are substantially less likely than males to cycle for transport in countries with low bicycle transport mode share. We investigated whether female commuter cyclists were more likely to use bicycle routes that provide separation from motor vehicle traffic. Methods. Census of cyclists observed at 15 locations (including off-road bicycle paths, on-road lanes and roads with no bicycle facilities) within a 7.4 km radius of the central business district (CBD) of Melbourne, Australia, during peak commuting times in February 2004. Results. 6589 cyclists were observed, comprising 5229 males (79.4%) and 1360 females (20.6%). After adjustment for distance of the bicycle facility from the CBD, females showed a preference for using off-road paths rather than roads with no bicycle facilities (odds ratio [OR]=1.43, 95% confidence interval [CI]: 1.12, 1.83), or roads with on-road bicycle lanes (OR=1.34, 95% CI: 1.03, 1.75). Conclusions. Consistent with gender differences in risk aversion, female commuter cyclists preferred to use routes with maximum separation from motorized traffic. Improved cycling infrastructure in the form of bicycle paths and lanes that provide a high degree of separation from motor traffic is likely to be important for increasing transportation cycling amongst under-represented population groups such as women.https://www.ncbi.nlm.nih.gov/pubmed/1769818
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BERA-TACTYC Early Childhood Research Review 2003-2017
BERA/TACTYC Review of Early Childhood Education and Care in the UK, 2003-2017 has involved a wide range of early childhood specialists, both in the early consultation stages, and in writing the five main sections of the Review. Teams of authors and their reference groups came together from TACTYC – the Association for Professional Development in Early Years, and the BERA Early Childhood Education and Care SIG. Using specific questions to interrogate the literature, each team worked on one of five main themes: Professionalism; Parenting and Family; Play and Pedagogy; Learning, Development and Curriculum, and Assessment and School Readiness. These themes are contextualised within broad policy issues in the UK.
The Introduction shows the working methods for the Review, and the Conclusion brings together key messages and suggestions for future research. We hope that the Review will prove useful to a range of early childhood specialists, including students, researchers, practitioners, policy makers and teachers in further and higher education. We intend to create a User Review that will be aimed at practitioners and to engage other stakeholders in current trends and debates.
The Review is being launched at a time of change and uncertainty within early childhood education and care, and we hope that the Review will provide a focal point for discussions about future directions in the four UK policy frameworks, the importance of research, and how we use research evidence to inform provision and practice
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