Precarious Employment and the Insertion of Young People in to the Labour Market

The decline of full-time open-ended contracts has led to the development of different types of precarious employment. In 2002, one in three people who had been in the labour market for less than five years were on a temporary employment contract. The conditions of insertion of young people in to the labour market worsened between the start of the 1980s and the end of the 1990s. The employment situation of people without a diploma compared to that of those most qualified was much more difficult at the end of the 1990s than at the start of the 1980s.Access to employment seems easier for holders of a higher education technical diploma (such as the DUT or the BTS) than for those holding a general education diploma, despite the equivalent length of their studies. The relative advantage for holders of a professional or technological baccalauréat is less apparent.School-to-Work Transition, Temporary Employment, Labour Mobility, Education

New magnetostatic modes in small nonellipsoidal magnetic particles

Magnetostatic normal modes are investigated here in elongated rods. The dipolar field resulting from the dipole-dipole interactions is calculated numerically in points of the axis connecting opposite rod face centers (\emph{central axis}) by collecting individual contributions to this field coming from each of the atomic planes perpendicular to the central axis. The applied magnetic field is assumed to be oriented along the central axis, and the magnetization to be uniform throughout the sample. The \emph{frequency} spectrum of magnetostatic waves propagating in the direction of the applied field is found numerically by solving the Landau-Lifshith equation of motion with the spatially \emph{nonhomogeneous} dipolar field taken into account; the mode amplitude \emph{profiles} are depicted as well. While energetically highest modes have \emph{bulk-extended} character, the modes forming the lower part of the spectrum are localized in the subsurface region (\emph{bulk-dead modes}). Between these two mode types, magnetostatic modes of a new type (\emph{comb modes}) are found to occur, characterized by two clearly discernible regions: a zone of fast amplitude oscillations inside the rod, and narrow slow-oscillation regions at the borders. Absorbing virtually no energy from an applied alternating field, comb modes will have no significant contribution to the magnetic noise.Comment: 16 pages, 6 figures, conferences paper: Physics of Magnetism'05, Poznan, Polan

Short-term contracts: trap or stepping stone toward stable employment?

This paper focuses on labor market transitions and especially on those involving fixed-term contracts. Our contribution is twofold: first, we provide an accurate measure of labor market transitions and focus on transitions from fixed-term contracts to open-ended contracts or unemployment (dealing with the "stepping-stone or dead-end" question) ; second, we analyze the potential incentive effect of fixed-term contracts on effort. To deal with unobserved heterogeneity, we use a dynamic multinomial logit with fixed effects. We estimate the model on the French Labor Force Survey (2002-2008) which provides detailed information on quarterly transitions. We construct an indicator of effort for fixed-term workers based on a compared weekly working time. We find that fixed-term contracts provide slightly better perspectives than unemployment. However, we don't find evidence of any significant impact of working more on the probability of getting an open-ended contract.Fixed-term contracts, effort, transitions

High temperature magnetic stabilization of cobalt nanoparticles by an antiferromagnetic proximity effect

Thermal activation tends to destroy the magnetic stability of small magnetic nanoparticles, with crucial implications in ultra-high density recording among other applications. Here we demonstrate that low blocking temperature ferromagnetic (FM) Co nanoparticles (TB<70 K) become magnetically stable above 400 K when embedded in a high N\'eel temperature antiferromagnetic (AFM) NiO matrix. The origin of this remarkable TB enhancement is due to a magnetic proximity effect between a thin CoO shell (with low N\'eel temperature, TN; and high anisotropy, KAFM) surrounding the Co nanoparticles and the NiO matrix (with high TN but low KAFM). This proximity effect yields an effective AFM with an apparent TN beyond that of bulk CoO, and an enhanced anisotropy compared to NiO. In turn, the Co core FM moment is stabilized against thermal fluctuations via core-shell exchange-bias coupling, leading to the observed TB increase. Mean-field calculations provide a semi-quantitative understanding of this magnetic- proximity stabilization mechanism