An Anatomy of the French Labour Market

[Excerpt] Over the last decades, many European countries have experienced high and persistent unemployment rates. The bulk of labour market research has tackled this issue by emphasizing the effect of employment protection legislation, hereafter EPL, on labour market performance. As a result, the importance of labour market flexibility has been widely acknowledged. This view can be summarized by the expressed desire of the E.U. council to give member States incentives to “review and, where appropriate, reform overly restrictive elements in employment legislation that affect labour market dynamics [...] and to undertake other appropriate measures to promote a better balance between work and private life and between flexibility and security”. It is however striking that most of the reforms undertaken have contrasted sharply with this latter recommendation by favouring reforms at the margin. Those reforms have fostered two-tier systems, as the increase in labour market flexibility has taken place mainly through a series of marginal reforms that liberalized the use of fixed-term and/or non-standard employment contracts. Two-tier systems have promoted the emergence of dual employment protection which can be broadly defined as the coexistence of both long-term contracts, which benefit from stringent protection, and short-term contracts with little or no protection. It is often argued that this combination creates labour market segmentation, traps workers in a recurring sequence of frequent unemployment spells, favours unequal repartition of risk between workers and enhances inequalities. In particular, two-tier systems create excess labour turnover as they increase the incentives to create temporary rather than permanent jobs, reduce job destruction for stable jobs, but increase churning for temporary jobs. For instance in countries with stringent legal constraints on the termination of permanent jobs, such as France or Spain, it turns out that about 70 per cent to 90 per cent of entries into employment are in temporary jobs with very short duration (on average less than one month and a half in France). If excess labour turnover and its consequences are a concern for the economy as a whole, the dramatic spread of temporary jobs is even more a concern for young/less experienced workers as they are more likely to be negatively affected by the adverse effects of dual employment protection. The French labour market is no exception and has faced similar trends during the 1990s. Given the pervasiveness of temporary jobs on the labour market and their consequences on the society and economic outcomes, it is urgent to understand how two-tier systems shape the functioning of the labour market. This is the very purpose of the present report. After having described in details the salient features of the French dual labour market and having discussed the legislation at the root of French dualism, we review the different mechanisms through which dualism affect labour markets: labour market dynamics, wage inequality, human capital accumulation, job satisfaction, social integration and health. We consider whenever possible both theoretical insights and empirical evaluations. We finally conclude this report by providing possible directions to reform the labour market

Enhancing the area of a Raman atom interferometer using a versatile double-diffraction technique

IIn this paper we demonstrate a new scheme for Raman transitions which realize a symmetric momentum-space splitting of $4 \hbar k$, deflecting the atomic wave-packets into the same internal state. Combining the advantages of Raman and Bragg diffraction, we achieve a three pulse state labelled interferometer, intrinsically insensitive to the main systematics and applicable to all kind of atomic sources. This splitting scheme can be extended to $4N \hbar k$ momentum transfer by a multipulse sequence and is implemented on a $8 \hbar k$ interferometer. We demonstrate the area enhancement by measuring inertial forces

Take-off of small Leidenfrost droplets

We put in evidence the unexpected behaviour of Leidenfrost droplets at the later stage of their evaporation. We predict and observe that, below a critical size $R_l$, the droplets spontaneously take-off due to the breakdown of the lubrication regime. We establish the theoretical relation between the droplet radius and its elevation. We predict that the vapour layer thickness increases when the droplets become smaller. A satisfactory agreement is found between the model and the experimental results performed on droplets of water and of ethanol.Comment: Accepted for publication in Phys. Rev. Lett. (2012

Fractional Laplacian matrix on the finite periodic linear chain and its periodic Riesz fractional derivative continuum limit

The 1D discrete fractional Laplacian operator on a cyclically closed (periodic) linear chain with finitenumber $N$ of identical particles is introduced. We suggest a "fractional elastic harmonic potential", and obtain the $N$-periodic fractionalLaplacian operator in the form of a power law matrix function for the finite chain ($N$ arbitrary not necessarily large) in explicit form.In the limiting case $N\rightarrow \infty$ this fractional Laplacian matrix recovers the fractional Laplacian matrix ofthe infinite chain.The lattice model contains two free material constants, the particle mass $\mu$ and a frequency$\Omega\_{\alpha}$.The "periodic string continuum limit" of the fractional lattice model is analyzed where lattice constant $h\rightarrow 0$and length $L=Nh$ of the chain ("string") is kept finite: Assuming finiteness of the total mass and totalelastic energy of the chain in the continuum limit leads to asymptotic scaling behavior for $h\rightarrow 0$ of thetwo material constants,namely $\mu \sim h$ and $\Omega\_{\alpha}^2 \sim h^{-\alpha}$. In this way we obtain the $L$-periodic fractional Laplacian (Riesz fractional derivative) kernel in explicit form.This $L$-periodic fractional Laplacian kernel recovers for $L\rightarrow\infty$the well known 1D infinite space fractional Laplacian (Riesz fractional derivative) kernel. When the scaling exponentof the Laplacian takesintegers, the fractional Laplacian kernel recovers, respectively, $L$-periodic and infinite space (localized) distributionalrepresentations of integer-order Laplacians.The results of this paper appear to beuseful for the analysis of fractional finite domain problems for instance in anomalous diffusion (L\'evy flights), fractional Quantum Mechanics,and the development of fractional discrete calculus on finite lattices