New Technologies, Workplace Organisation and the Age Structure of the Workforce: Firm-Level Evidence

This paper investigates the relationships between new technologies, innovative workplace practices and the age structure of the workforce in a sample of French manufacturing firms. We find evidence that the wage bill share of older workers is lower in innovative firms and that the opposite holds for younger workers. This age bias is also evidenced within occupational groups, thus suggesting that skills do not completely protect workers against the labour market consequences of ageing. More detailed analysis of employment inflows and outflows shows that new technologies essentially affect older workers through reduced hiring opportunities, whereas organisational innovations mainly increase their probability of exit. This suggests that some skill obsolescence may be at work in our sample.new work practices, technology, older workers, labour demand

Expected performances of a Laue lens made with bent crystals

In the context of the LAUE project devoted to build a Laue lens prototype for focusing celestial hard X-/soft gamma-rays, a Laue lens made of bent crystal tiles, with 20 m focal length, is simulated. The focusing energy passband is assumed to be 90--600 keV. The distortion of the image produced by the lens on the focal plane, due to effects of crystal tile misalignment and radial distortion of the crystal curvature, is investigated. The corresponding effective area of the lens, its point spread function and sensitivity are calculated and compared with those exhibited by a nominal Laue lens with no misalignment and/or distortion. Such analysis is crucial to estimate the optical properties of a real lens, in which the investigated shortcomings could be present.Comment: 20 pages, 14 figure

Interplay between shear loading and structural aging in a physical gel

We show that the aging of the mechanical relaxation of a gelatin gel exhibits the same scaling phenomenology as polymer and colloidal glasses. Besides, gelatin is known to exhibit logarithmic structural aging (stiffening). We find that stress accelerates this process. However, this effect is definitely irreducible to a mere age shift with respect to natural aging. We suggest that it is interpretable in terms of elastically-aided elementary (coil$\to$helix) local events whose dynamics gradually slows down as aging increases geometric frustration

Comment on "Scaling of the quasiparticle spectrum for d-wave superconductors"

In a recent Letter Simon and Lee suggested a scaling law for thermodynamic and kinetic properties of superconductors with lines of gap nodes. However their crossover parameter between the bulk dominated regime and the vortex dominated regime is different from that found in our paper (N.B. Kopnin and G.E. Volovik, JETP Lett., {\bf 64}, 690 (1996); see also cond-mat/9702093). We discuss the origin of the disagreement.Comment: submitted to Physical Review Letters as "Comment" to the paper by S.H. Simon and P.A. Lee, Phys. Rev. Lett., 78 (1997) 1548 (cond-mat/9611133

Compton telescope with coded aperture mask: Imaging with the INTEGRAL/IBIS Compton mode

Compton telescopes provide a good sensitivity over a wide field of view in the difficult energy range running from a few hundred keV to several MeV. Their angular resolution is, however, poor and strongly energy dependent. We present a novel experimental design associating a coded mask and a Compton detection unit to overcome these pitfalls. It maintains the Compton performance while improving the angular resolution by at least an order of magnitude in the field of view subtended by the mask. This improvement is obtained only at the expense of the efficiency that is reduced by a factor of two. In addition, the background corrections benefit from the coded mask technique, i.e. a simultaneous measurement of the source and background. This design is implemented and tested using the IBIS telescope on board the INTEGRAL satellite to construct images with a 12' resolution over a 29 degrees x 29 degrees field of view in the energy range from 200 keV to a few MeV. The details of the analysis method and the resulting telescope performance, particularly in terms of sensitivity, are presented

STUDI SULLA BIPARTIZIONE DEL PROCESSO PRIVATO ROMANO

The PhD thesis, titled \u201cStudi sulla bipartizione del processo privato romano\u201d (Studies on the bipartition of the Roman private trial), is entirely devoted to the structure of the Roman private trial during its early centuries of development. The trial per legis actiones and the trial per fomulas were in fact structured over two distinct phases: a phase \u2013 in iure \u2013 before the magistrate with iurisdictio and another one \u2013 apud iudicem \u2013 before a judge, usually a private citizen, invested with the power to decide the matter of the dispute. The theme, not taken into much depth by roman law scholarship, emerges in some studies devoted to other aspects of the trial. This thesis has highlighted the derivation of bipartition from the necessity, emerged towards the end of the monarchical era, to rationalize dispute resolution tools. Another issue is that of the relationship between law and religion in the Roman legal order: in the thesis it is argued that Roman law has never come to a clear separation of law and religion but, on the contrary, magic-religious elements, typical of the archaic era, still remain in preclassical and classical times, as it is evident in some law institutes, such as the sacramentum and the litis contestatio

Computer Aided Analysis, Planning, and Control of Space Systems Operations

The complexity and operational dynamics of modern space systems has dictated a need for computerized tools to assist in the analysis, planning, and control of space system operations. Three computer programs (ACTNET, TLGEN, and WICK 9) which have been applied successfully to these problems are discussed in this paper. ACTNET is a second generation discrete-event simulation system designed for the functional analysis of complex processes. It is applicable to systems which may be modeled as networks of activities that are constrained by precedence, logical conditions, and limited resources. ACTNET has been employed within the Nuclear Stage, Space Station, and Space Shuttle programs by MDAC-West. TLGEN is a computer program currently under development by MDAC-West for generating operational mission timelines. In its batch mode of operation, it is used for planning on-orbit operations. In its interactive (on-line) mode, it can support real-time control of on-orbit operations by mission control/ground system personnel. TLGEN is designed for scheduling detailed sequences of events subject to event duration time, execution time, priority, resource usage, and environmental constraints (ephemeris)

Elastic precession of electronic spin states in interacting integer quantum Hall edge channels

We consider the effect of Coulomb interactions in the propagation of electrons, prepared in arbitrary spin states, on chiral edge channels in the integer quantum Hall regime. Electrons are injected and detected at the same energy at different locations of the Hall bar, which is modeled as a chiral Tomonaga-Luttinger liquid. The current is computed perturbatively in the tunneling amplitudes, within a non-crossing approximation using exact solutions of the interacting Green's functions. In the case of different channel velocities, the spin precession effect is evaluated, and the role of interaction parameters and wavevectors is discussed.Comment: 5 pages, 3 figure