Measuring Competences in School-leaver Surveys

The measurement of competences is a relatively new topic in the economic science. In the past, economists have usually measured worker competences by educational background, tenure, or other simple quantifiable indicators. In the transition from the industrial to the knowledge economy, however, this classical approach has become rather unsatisfactory. Individual labour market performance is no longer dependent on just the individual’s initial education, since todays labour market requires continuous learning and development throughout the career. Employability has become a key concept in the knowledge economy, and the traditional lifetime employment career in a single firm has been replaced by what has been termed the protean career (Hall and Moss, 1998). In such a career, the person, not the firm, is the managing agent. In order to measure or predict career success, uni-dimensional indicators such as educational background that economists have used in the past are no longer sufficient. In the modern economy, skills and knowledge are the main factors in production, and the measurement of competences is a logical step in determining and predicting individual labour market success more accurately and reliably.education, training and the labour market;

Monitoring data in R with the lumberjack package

Monitoring data while it is processed and transformed can yield detailed insight into the dynamics of a (running) production system. The lumberjack package is a lightweight package allowing users to follow how an R object is transformed as it is manipulated by R code. The package abstracts all logging code from the user, who only needs to specify which objects are logged and what information should be logged. A few default loggers are included with the package but the package is extensible through user-defined logger objects.Comment: Accepted for publication in the Journal of Statistical Softwar

Skills Obsolescence: Causes and Cures

Until now there has been surprisingly little research on the causes of and the remedies for skills obsolescence. This study tries to fill that gap to some extent by analysing the relation between risk factors and skills obsolescence. Moreover, the role remedies play to counter skills obsolescence is analysed. Four empirical analyses that relate skills obsolescence to risk factors and remedies are presented. We find that most risk factors identified in the literature can be validated empirically. The remedies for skills obsolescence are not effective in all situations: the results show that there is considerable variation in the effectiveness of the remedies across different types of skills obsolescence. Although current available data does not allow a comprehensive analysis, which also takes account of relations between the various types of skills obsolescence, the results obtained are plausible and offer a starting point for further research.education, training and the labour market;

Germanium-on-silicon mid-infrared waveguides and Mach-Zehnder interferometers

In this paper we describe Ge-on-Si waveguides and Mach-Zehnder interferometers operating in the 5.2 - 5.4 mu m wavelength range. 3dB/cm waveguide losses and Mach-Zehnder interferometers with 20dB extinction ratio are presented

Molecular biological methods for studying the gut microbiota : the EU human gut flora project

Seven European laboratories co-operated in a joint project (FAIR CT97-3035) to develop, refine and apply molecular methods towards facilitating elucidation of the complex composition of the human intestinal microflora and to devise robust methodologies for monitoring the gut flora in response to diet. An extensive database of 16S rRNA sequences for tracking intestinal bacteria was generated by sequencing the 16S rRNA genes of new faecal isolates and of clones obtained by amplification with polymerase chain reaction (PCR) on faecal DNA from subjects belonging to different age groups. The analyses indicated that the number of different species (diversity) present in the human gut increased with age. The sequence information generated, provided the basis for design of 16S rRNA-directed oligonucleotide probes to specifically detect bacteria at various levels of phylogenetic hierarchy. The probes were tested for their specificity and used in whole-cell and dot-blot hybridisations. The applicability of the developed methods was demonstrated in several studies and the major outcomes are described

Shock-triggered formation of magnetically-dominated clouds

To understand the formation of a magnetically dominated molecular cloud out of an atomic cloud, we follow the dynamical evolution of the cloud with a time-dependent axisymmetric magnetohydrodynamic code. A thermally stable warm atomic cloud is initially in static equilibrium with the surrounding hot ionised gas. A shock propagating through the hot medium interacts with the cloud. As a fast-mode shock propagates through the cloud, the gas behind it becomes thermally unstable. The $\beta$ value of the gas also becomes much smaller than the initial value of order unity. These conditions are ideal for magnetohydrodynamic waves to produce high-density clumps embedded in a rarefied warm medium. A slow-mode shock follows the fast-mode shock. Behind this shock a dense shell forms, which subsequently fragments. This is a primary region for the formation of massive stars. Our simulations show that only weak and moderate-strength shocks can form cold clouds which have properties typical of giant molecular clouds.Comment: 7 pages, 6 figures, accepted by Astronomy and Astrophysic

Direct measurement of the radiative lifetime of vibrationally excited OH radicals

Neutral molecules, isolated in the gas-phase, can be prepared in a long-lived excited state and stored in a trap. The long observation time afforded by the trap can then be exploited to measure the radiative lifetime of this state by monitoring the temporal decay of the population in the trap. This method is demonstrated here and used to benchmark the Einstein $A$-coefficients in the Meinel system of OH. A pulsed beam of vibrationally excited OH radicals is Stark decelerated and loaded into an electrostatic quadrupole trap. The radiative lifetime of the upper $\Lambda$-doublet component of the $X ^2\Pi_{3/2}, v=1, J=3/2$ level is determined as $59.0 \pm 2.0$ ms, in good agreement with the calculated value of $57.7 \pm 1.0$ ms.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let