Le parc véhicules légers du CERN

La création d'un parc central de véhicules légers (Car Pool) a été décidée en janvier 1991. Le fonctionnement et l'évaluation des co ts du Car Pool sont gérés par un Comité des Utilisateurs composé de représentants divisionnaires et de deux membres permanents du Groupe ST-HM. La section Logistique de ce Groupe exploite le parc en tant qu'unité autofinancée en louant ses véhicules aux utilisateurs à titre permanent ou à court terme. L'objet de la présentation consiste à décrire le principe de fonctionnement du Car Pool et les moyens mis en oeuvre pour en assurer la gestion technique, administrative et financière. Les différents objectifs à atteindre portent sur la contribution apportée par les Divisions (location annuelle), l'utilisation rationnelle des voitures (kilomètres parcourus, entretien, réparations), la mise en place d'une administration simplifiée pour les utilisateurs et le suivi de l'évolution de ce parc compte tenu des modèles actuellement sur le marché de l'automobile

Shubnikov-de Haas oscillations in SrTiO3\LaAlO3 interface

Quantum magnetic oscillations in SrTiO3/\LaAlO3 interface are observed. The evolution of their frequency and amplitude at various gate voltages and temperatures is studied. The data are consistent with the Shubnikov de-Haas theory. The Hall resistivity rho exhibits nonlinearity at low magnetic field. It is fitted assuming multiple carrier contributions. The comparison between the mobile carrier density inferred from the Hall data and the oscillation frequency suggests multiple valley and spin degeneracy. The small amplitude of the oscillations is discussed in the framework of the multiple band scenario

Tuning spin-orbit coupling and superconductivity at the SrTiO3/LaAlO3 interface: a magneto-transport study

The superconducting transition temperature, Tc, of the SrTiO3/LaAlO3 interface was varied by the electric field effect. The anisotropy of the upper critical field and the normal state magneto-transport were studied as a function of gate voltage. The spin-orbit coupling energy is extracted. This tunable energy scale is used to explain the strong gate dependence of the mobility and of the anomalous Hall signal observed. The spin-orbit coupling energy follows Tc for the electric field range under study

Phase coherent transport in SrTiO3/LaAlO3 interfaces

The two dimensional electron gas formed between the two band insulators SrTiO3 and LaAlO3 exhibits a variety of interesting physical properties which make it an appealing material for use in future spintronics and/or quantum computing devices. For this kind of applications electrons have to retain their phase memory for sufficiently long times or length. Using a mesoscopic size device we were able to extract the phase coherence length, and its temperature variation. We find the dephasing rate to have a power law dependence on temperature. The power depends on the temperature range studied and sheet resistance as expected from dephasing due to strong electron-electron interactions.Comment: Submitted to Phys. Rev

Evolution of a bosonic mode across the superconducting dome in the high-Tc cuprate Pr(2-x)Ce(x)CuO(4-{\delta})

We report a detailed spectroscopic study of the electron doped cuprate superconductor Pr(2-x)Ce(x)CuO(4-{\delta}) using point contact junctions for x=0.125(underdoped), x=0.15(optimally doped) and x=0.17(overdoped). From our conductance measurements we are able to identify bosonic resonances for each doping. These excitations disappear above the critical temperature, and above the critical magnetic field. We find that the energy of the bosonic excitations decreases with doping, which excludes lattice vibrations as the paring glue. We conclude that the bosonic mediator for these cuprates is more likely to be spin excitations.Comment: 4 page

The Liberal Commons

Following the Civil War, black Americans began acquiring land in earnest; by 1920 almost one million black families owned farms. Since then, black rural landownership has dropped by more than 98% and continues in rapid decline – there are now fewer than 19,000 black-operated farms left in America. By contrast, white-operated farms dropped only by half, from about 5.5 million to 2.4 million. Commentators have offered as partial explanations the consolidation of inefficient small farms and intense racial discrimination in farm lending. However, even absent these factors, the unintended effects of old-fashioned American property law might have led to the same outcome. Because black farmers often did not make wills, their heirs took the land as co-owners. Over generations, co-owners multiplied, the farms became unmanageable, and the land was partitioned and sold, a seemingly inevitable tragedy of the commons in which too many owners waste a common resource. Black rural landownership may seem a dusty topic, peopled with hardscrabble tales of property past. Consider, though, the daunting possibility that property future – think biomedical research, post-apartheid restitution, hybrid residential associations, perhaps cyberspace – may have the same analytic structure, be subject to a similar punishing legal regime, and face the same fate as the black rural landowner. Overcoming the tragic fate of commons property should not be so hard. Until now, however, legal theorists have often worked within a framework that makes happier solutions difficult to imagine. Typically, theorists have relied on a thin utilitarian language yoked to a narrow conceptual map of property. One school, worrying that rational owners will overconsume commons resources, has embraced the so-called Biackstonian image of private property with sole and despotic dominion at the core. Another school, after showing how small, close-knit groups can successfully conserve commons resources if they sharply restrict exit, has advocated a version of commons property. For both schools, the image of tragic outcomes proves an ideal foil, one that implicitly points theorists toward their preferred normative solutions. Privatization seems inevitable for utilitarians with a liberal bent, because they believe that locking people together violates a fundamental concern for individual autonomy. By contrast, illiberal communitarian solutions seem relatively attractive to those who are ready to sacrifice individual autonomy for collective goals. While these underlying normative commitments drive the familiar debate over tragic outcomes, they never surface as the focus for analysis of commons resource management

Can Contract Emancipate? Contract Theory and The Law of Work

Contract and employment law have grown apart. Long ago, each side gave up on the other. In this Article, we re-unite them to the betterment of both. In brief, we demonstrate the emancipatory potential of contract for the law of work. Today, the dominant contract theories assume a widget transaction between substantively equal parties. If this were an accurate description of what contract is, then contract law would be right to expel workers. Worker protections would indeed be better regulated by – and relegated to – employment and labor law. But contract law is not what contract theorists claim. Neither is contract law what the dominant employment theorists fear – a domain that necessarily misses the constitutive place of work in people’s life-plans and overlooks the systemic vulnerability of workers to their employers. Contract, we contend, need not be work law’s canonical “other.” The first step is to see that contract, rightly understood, is an autonomy-enhancing device, one founded on the fundamental liberal commitment of reciprocal respect for self-determination. From this “choice theory” perspective, the presumed opposition between employment and contract law dissolves. We show that many employment law doctrines are not external to contract, but are instead entailed in liberal contract itself. Grounding worker protections in contract theory has two positive effects. First, it offers workers more secure protection than reliance on momentary public law compromises. Second, it reveals contract’s emancipatory potential for all of us – not just as workers, but even as widget buyers. Contract can empower, and employment can show us the wa