Occupational mobility within and between skill clusters: an empirical analysis based on the skill-weights approach

This paper applies Lazear\u27s skill-weights approach (2009) to analyze the specificity of skill combinations of various occupations and its effects on occupational mobility and wages. The results show that the more specific an occupation, the smaller the probability of an occupational change. We also identify clusters of occupations characterized by similar skill combinations and find that employees in specific occupations have a comparatively higher probability of changing occupations within a skill cluster than between skill clusters. Moreover, occupational mobility within a skill cluster results in wage gains, while between clusters it results in wage losses. Therefore, the acquired skill combination and the resulting skill cluster, rather than the occupation per se, crucially determines mobility. Thus, for educational policies, it is more important to study whether a skill cluster is sustainable than an occupation. (DIPF/Orig.

MicroPoem: experimental investigation of birch pollen emissions

Diseases due to aeroallergens constantly increased over the last decades and affect more and more people. Adequate protective and pre-emptive measures require both reliable assessment of production and release of various pollen species, and the forecasting of their atmospheric dispersion. Pollen forecast models, which may be either based on statistical knowledge or full physical transport and dispersion modeling, can provide pollen forecasts with full spatial coverage. Such models are currently being developed in many countries. The most important shortcoming in these pollen transport systems is the description of emissions, namely the dependence of the emission rate on physical processes such as turbulent exchange or mean transport and biological processes such as ripening (temperature) and preparedness for release. Thus the quantification of pollen emissions and determination of the governing mesoscale and micrometeorological factors are subject of the present project MicroPoem, which includes experimental field work as well as numerical modeling. The overall goal of the project is to derive an emission parameterization based on meteorological parameters, eventually leading to enhanced pollen forecasts. In order to have a well-defined source location, an isolated birch pollen stand was chosen for the set-up of a ‘natural tracer experiment', which was conducted during the birch pollen season in spring 2009. The site was located in a broad valley, where a mountain-plains wind system usually became effective during clear weather periods. This condition allowed to presume a rather persistent wind direction and considerable velocity during day- and nighttime. Several micrometeorological towers were operated up- and downwind of this reference source and an array of 26 pollen traps was laid out to observe the spatio-temporal variability of pollen concentrations. Additionally, the lower boundary layer was probed by means of a sodar and a tethered balloon system (also yielding a pollen concentration profile). In the present contribution a project overview is given and first results are presented. An emphasis is put on the relative performance of different sample technologies and the corresponding relative calibration in the lab and the field. The concentration distribution downwind of the birch stand exhibits a significant spatial (and temporal) variability. Small-scale numerical dispersion modeling will be used to infer the emission characteristics that optimally explain the observed concentration patterns

Characterizations of pretameness and the Ord-cc

It is well known that pretameness implies the forcing theorem, and that pretameness is characterized by the preservation of the axioms of $\mathsf{ZF}^-$, that is $\mathsf{ZF}$ without the power set axiom, or equivalently, by the preservation of the axiom scheme of replacement, for class forcing over models of $\mathsf{ZF}$. We show that pretameness in fact has various other characterizations, for instance in terms of the forcing theorem, the preservation of the axiom scheme of separation, the forcing equivalence of partial orders and their dense suborders, and the existence of nice names for sets of ordinals. These results show that pretameness is a strong dividing line between well and badly behaved notions of class forcing, and that it is exactly the right notion to consider in applications of class forcing. Furthermore, for most properties under consideration, we also present a corresponding characterization of the $\mathrm{Ord}$-chain condition

Vergleichende Qualitätsforschung - Neue Ansätze und Impulse täten gut

Eine am FiBL durchgeführte Auswertung neuer Studien im Bereich der vergleichenden Qualitätsforschung brachte die Bestätigung bekannter Befunde und Tendenzen, zeigte aber keine grundsätzlich neuen Ansätze. Für den biologischen Landbau bleibt die Qualitätsforschung von zentraler Bedeutung

Guideline for handling pesticide residues in Czech organic production

This document was prepared in the project «Development of guidelines for the use of pesticide analysis in organic inspection in the Czech Republic (sampling, evaluation and interpretation)». At the beginning of this project, a workshop with stakeholders was held. The present document builds on the outcomes of this workshop, and elaborates guidance for all stakeholders involved in Czech organic production and its control, on how to deal with residue analyses. In recognition of the European dimension of the problem, the project followed a two-step approach. In the first step, the present guideline was prepared. It is written in a general style and in the English language, so that it potentially applies for many countries. Although the current project aims specifically at the situation in the Czech Republic, its use for other countries is welcome! In the second step, a national guideline for the Czech Republic will be prepared, based on this document. The present document will serve as a blueprint for this guideline, which will be tailored to the specific situation in the Czech Republic and written in the Czech language. The aim is that all control bodies and authorities dealing with organic production and organic products in the Czech Republic will use this guideline

Generating entanglement between two-dimensional cavities in uniform acceleration

Moving cavities promise to be a suitable system for relativistic quantum information processing. It has been shown that an inertial and a uniformly accelerated one-dimensional cavity can become entangled by letting an atom emit an excitation while it passes through the cavities, but the acceleration degrades the ability to generate entanglement. We show that in the two-dimensional case the entanglement generated is affected not only by the cavity's acceleration but also by its transverse dimension which plays the role of an effective mass