Diversity of Contract Law and the European Internal Market

This contribution discusses the question whether diversity of contract law among the European member states is a barrier to cross-border trade. This question is important in view of the ongoing debate about the need for a unified European private law. It has tried to answer the question by building upon insights from psychology, economics and law. It turns out that no definitive answer can be given to the question whether the savings in transaction costs through the removal of legal diversity are greater than the losses caused by the termination of competition of legal systems.Unification; Contract Law

Occupation Specific or Generic Skills? Conflicting Interests of Firms and Apprentices

Firms and apprentices have conflicting interests with respect to the content of training programmes. On the basis of a model for the investment decision in occupation-specific and generic training, I will show that, in the case of imperfect competition, firms are not only unwilling to pay for generic training, they also want this component to be as low as possible because it decreases their expected returns to occupation-specific training. Therefore the generic component of the training will be below the social optimum. This underinvestment problem cannot always be solved by having the generic component fixed at the social optimum by an external training body. Fixing the generic component may negatively affect the level of occupation-specific training and decrease social welfare.education, training and the labour market;

The dynamics and control of fluctuating pressure loads in the reattachment region of a supersonic free shear layer

The primary aim is to investigate the mechanisms which cause the unsteady wall-pressure fluctuations in shock wave turbulent shear layer interactions. The secondary aim is to find means to reduce the magnitude of the fluctuating pressure loads by controlling the unsteady shock motion. The particular flow proposed for study is the unsteady shock wave interaction formed in the reattachment zone of a separated supersonic flow. Similar flows are encountered in many practical situations, and they are associated with high levels of fluctuating wall pressure. Wall pressure fluctuations were measured in the reattachment region of the supersonic free shear layer. The free shear layer was formed by the separation of a Mach 2.9 turbulent boundary layer from a backward facing step. Reattachment occurred on a 20 deg ramp. By adjusting the position of the ramp, the base pressure was set equal to the freestream pressure, and the free shear layer formed in the absence of a separation shock. An array of flush-mounted, miniature, high-frequency pressure transducers was used to make multichannel measurements of the fluctuating wall pressure in the vicinity of the reattachment region. Contrary to previous observations of this flow, the reattachment region was found to be highly unsteady, and the pressure fluctuations were found to be significant. The overall behavior of the wall pressure loading is similar in scale and magnitude to the unsteadiness of the wall pressure field in compression ramp flows at the same Mach number. Rayleigh scattering was used to visualize the instantaneous shock structure in the streamwise and spanwise direction. Spanwise wrinkles on the order of half the boundary layer thickness were observed

Turbulence modeling in shock wave/turbulent boundary layer interactions

The research performed was an experimental program to help develop turbulence models for shock wave boundary layer interactions. The measurements were taken in a Mach 3, 16 deg compression corner interaction, at a unit Reynolds number of 63 x 10(exp 6)/m. The data consisted of heat transfer data taken upstream and downstream of the interaction, hot wire measurements of the instantaneous temperature and velocity fluctuations to verify the Strong Reynolds Analogy, and single- and double-pulsed Rayleigh scattering images to study the development of the instantaneous shock/turbulence interaction

Three-dimensional structure of a low-Reynolds-number turbulent boundary layer

A low-Reynolds-number zero-pressure-gradient incompressible turbulent boundary layer was investigated using a volumetric imaging technique. The Reynolds number based on momentum thickness was 700. The flow was tagged with a passive scalar from two spanwise dye slots to distinguish between fluid motions originating in the inner and outer portions of the boundary layer. The resulting volumetric scalar field was interrogated using a laser sheet scanner developed for this study. Two- and three-dimensional time-dependent visualizations of a 50 volume time series are presented (equivalent to 17δ in length). In the outer portion of the boundary layer, scalar structures were observed to lie along lines in the (x, z)-plane, inclined to the streamwise (x-)direction in the range ±50°. The ejection of brightly dyed fluid packets from the near-wall region was observed to be spatially organized, and related to the passage of the large-scale scalar structures.Carl J Delo, Richard M Kelson and Alexander J Smit

jsPhyloSVG: A Javascript Library for Visualizing Interactive and Vector-Based Phylogenetic Trees on the Web

BackgroundMany software packages have been developed to address the need for generating phylogenetic trees intended for print. With an increased use of the web to disseminate scientific literature, there is a need for phylogenetic trees to be viewable across many types of devices and feature some of the interactive elements that are integral to the browsing experience. We propose a novel approach for publishing interactive phylogenetic trees. Methods/Principal Findings We present a javascript library, jsPhyloSVG, which facilitates constructing interactive phylogenetic trees from raw Newick or phyloXML formats directly within the browser in Scalable Vector Graphics (SVG) format. It is designed to work across all major browsers and renders an alternative format for those browsers that do not support SVG. The library provides tools for building rectangular and circular phylograms with integrated charting. Interactive features may be integrated and made to respond to events such as clicks on any element of the tree, including labels. Conclusions/Significance jsPhyloSVG is an open-source solution for rendering dynamic phylogenetic trees. It is capable of generating complex and interactive phylogenetic trees across all major browsers without the need for plugins. It is novel in supporting the ability to interpret the tree inference formats directly, exposing the underlying markup to data-mining services. The library source code, extensive documentation and live examples are freely accessible at www.jsphylosvg.com

Radiative Transfer Effects in He I Emission Lines

We consider the effect of optical depth of the 2 ^{3}S level on the nebular recombination spectrum of He I for a spherically symmetric nebula with no systematic velocity gradients. These calculations, using many improvements in atomic data, can be used in place of the earlier calculations of Robbins. We give representative Case B line fluxes for UV, optical, and IR emission lines over a range of physical conditions: T=5000-20000 K, n_{e}=1-10^{8} cm^{-3}, and tau_{3889}=0-100. A FORTRAN program for calculating emissivities for all lines arising from quantum levels with n < 11 is also available from the authors. We present a special set of fitting formulae for the physical conditions relevant to low metallicity extragalactic H II regions: T=12,000-20,000 K, n_{e}=1-300 cm^{-3}, and tau_{3889} < 2.0. For this range of physical conditions, the Case B line fluxes of the bright optical lines 4471 A, 5876 A, and 6678 A, are changed less than 1%, in agreement with previous studies. However, the 7065 A corrections are much smaller than those calculated by Izotov & Thuan based on the earlier calculations by Robbins. This means that the 7065 A line is a better density diagnostic than previously thought. Two corrections to the fitting functions calculated in our previous work are also given.Comment: To be published in 10 April 2002 ApJ; relevant code available at ftp://wisp.physics.wisc.edu/pub/benjamin/Heliu