The social balance sheet 2007

According to the results of the social balance sheets available in September 2008, employment rose by 2.3 p.c. in 2007. The increase concerned both full-time as well as part-time workers. The rise in part-time working is only partially explained by the hiring of part-time workers : this year again, medium-sized and large enterprises also saw numerous changes in working arrangements. Although women still account for the bulk of part-time workers, the increase in the part-time rate was greater for men than for women. The analysis shows that part-time working is spread unevenly in the various branches of activity. As in previous years, the article studies staff movements and the characteristics of workers joining and leaving companies filing full-format accounts. It also examines reasons for leaving and the external turnover of workers by comparing the results from the various groups of enterprises categorised according to their size or their branch of activity. The analysis also highlights the further advance in 2007 of temporary employment contracts – whose proportion is tending to become more uniform in the various categories of company size – and the increased use of agency work in companies filing full-format accounts. Recourse to these contracts as instruments for workforce adjustments varies considerably from one branch of activity to the other. The total wage bill rose by 5.1 p.c. between 2006 and 2007 in the reduced population of companies. Over the same period there was a 2.3 p.c. growth in the number of hours worked, so that hourly labour costs grew by 2.8 p.c. on average. The rise was more pronounced for full-time than for part-time workers. Major differences in levels are still discernible in terms of hourly costs, depending on the size and branch of activity of the companies. In terms of training, the results for 2006 still fall well short of the set targets : training costs accounted for 1.17 p.c. of the total wage bill whereas the target specified in the Generation Pact for this same year was 1.9 p.c. At the same time, the participation rate in training was only 35.2 p.c. whereas a target has been set of 50 p.c. by 2010. Growth was nevertheless recorded between 2006 and 2007 within a favourable economic context : the cost indicator for training grew by 4 p.c. and the participation rate by 0.2 p.c. If these increases were applied to the level observed in 2006, these same indicators should amount to 1.22 and 35.3 p.c. respectively for 2007.employment, staff costs, training, working hours, employment contract, full-time, part-time, skills, temporary worker

Comment about constraints on nanometer-range modifications to gravity from low-energy neutron experiments

A topic of present interest is the application of experimentally observed quantum mechanical levels of ultra-cold neutrons in the earth's gravitational field for searching short-range modifications to gravity. A constraint on new forces in the nanometer-range published by Nesvizhevsky and Protasov follows from inadequate modelling of the interaction potential of a neutron with a mirror wall. Limits by many orders of magnitude better were already derived long ago from the consistency of experiments on the neutron-electron interaction.Comment: three page

One-step replica symmetry breaking solution for a highly asymmetric two-sublattice fermionic Ising spin glass model in a transverse field

The one-step replica symmetry breaking (RSB) is used to study a two-sublattice fermionic infinite-range Ising spin glass (SG) model in a transverse field $\Gamma$. The problem is formulated in a Grassmann path integral formalism within the static approximation. In this model, a parallel magnetic field $H$ breaks the symmetry of the sublattices. It destroys the antiferromagnetic (AF) order, but it can favor the nonergodic mixed phase (SG+AF) characterizing an asymmetric RSB region. In this region, intra-sublattice disordered interactions $V$ increase the difference between the RSB solutions of each sublattice. The freezing temperature shows a higher increase with $H$ when $V$ enhances. A discontinue phase transition from the replica symmetry (RS) solution to the RSB solution can appear with the presence of an intra-sublattice ferromagnetic average coupling. The $\Gamma$ field introduces a quantum spin flip mechanism that suppresses the magnetic orders leading them to quantum critical points. Results suggest that the quantum effects are not able to restore the RS solution. However, in the asymmetric RSB region, $\Gamma$ can produce a stable RS solution at any finite temperature for a particular sublattice while the other sublattice still presents RSB solution for the special case in which only the intra-sublattice spins couple with disordered interactions.Comment: 11 pages, 8 figures, accepted for publication in Phys. Rev.

Local 3Qy betatron resonance correction in the 2012 RHIC 250 GeV run

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Role of dynamic Jahn-Teller distortions in Na2C60 and Na2CsC60 studied by NMR

Through 13C NMR spin lattice relaxation (T1) measurements in cubic Na2C60, we detect a gap in its electronic excitations, similar to that observed in tetragonal A4C60. This establishes that Jahn-Teller distortions (JTD) and strong electronic correlations must be considered to understand the behaviour of even electron systems, regardless of the structure. Furthermore, in metallic Na2CsC60, a similar contribution to T1 is also detected for 13C and 133Cs NMR, implying the occurence of excitations typical of JT distorted C60^{2-} (or equivalently C60^{4-}). This supports the idea that dynamic JTD can induce attractive electronic interactions in odd electron systems.Comment: 3 figure

Searches for sterile neutrinos and axionlike particles from the Galactic halo with eROSITA

Dark matter might be made of "warm" particles, such as sterile neutrinos in the keV mass range, which can decay into photons through mixing and are consequently detectable by X-ray telescopes. Axionlike particles (ALPs) are detectable by X-ray telescopes too when coupled to standard model particles and decay into photons in the keV range. Both particles could explain the unidentified 3.5 keV line and, interestingly, XENON1T observed an excess of electron recoil events most prominent at 2-3 keV. One explanation could be an ALPs origin, which is not yet excluded by X-ray constraints in an anomaly-free symmetry model in which the photon production is suppressed. We study the diffuse emission coming from the Galactic halo, and calculate the sensitivity of all-sky X-ray survey performed by eROSITA to identify a sterile neutrino or ALP dark matter. We estimate bounds on the mixing angle of the sterile neutrinos and coupling strength of the ALPs. After four years of data-taking by eROSITA, we expect to set stringent constraints, and in particular, we expect to firmly probe mixing angle $\sin^2(2\theta)$ up to nearly two orders magnitude below the best-fit value for explaining the unidentified 3.5 keV line. Moreover, with eROSITA, we will be able to probe the ALP parameter space of couplings to photons and electrons, and potentially confirm an ALP origin of the XENON1T excess.Comment: 8 pages, 6 figures; Comments welcome; Matches version accepted for publication in PR