Le droit suisse des sociétés en 2017: modifications législatives, jurisprudence et doctrine

La contribution présente, sous une forme synthétique, les principales modifications législatives, entrées en vigueur et en cours, la jurisprudence ainsi que la doctrine publiée en droit suisse des sociétés en 2017. Les modifications législatives (I.) accordent une large place à la présentation de la révision projetée du droit de la société anonyme, tout en s’intéressant également à d’autres thèmes, tel que l’initiative populaire « Entreprises responsables - pour protéger l’être humain et l’environnement ». Les résumés de jurisprudence sont classés par forme de société et décrivent en premier lieu les arrêts publiés (II.). Finalement, la doctrine est présentée en fonction du thème traité (III.)

Mechanics of the Ski-Snow Contact

Two outstanding questions of the ski-snow friction are considered: the deformation mode of the snow and the real contact area. The deformation of hard, well sintered snow in a short time impact has been measured with a special linear friction tester. Four types of deformations have been identified: brittle fracture of bonds, plastic deformation of ice at the contact spots, elastic and delayed elastic deformation of the snow matrix. The latter is the dominant deformation in the ski-snow contact. Based on the measured loading curves the mechanical energy dissipation of snow deformation in skiing on hard snow has been determined and found negligible compared to the thermal energy dissipation. A mechanical model consisting of ice spheres supported by rheological elements (a non-linear spring in series with a Kelvin element) is proposed to model the deformation of snow in the ski-snow contact. The model can describe the delayed elastic behaviour of snow. Coupled with the complete topographical description of the snow surface obtained from X-ray micro computer tomography measurements, the model predicts the number and area of contact spots between ski and snow. An average contact spot size of 110μm, and a relative real contact area of 0.4% has been foun

Observation of Coulomb-Assisted Dipole-Forbidden Intraexciton Transitions in Semiconductors

We use terahertz pulses to induce resonant transitions between the eigenstates of optically generated exciton populations in a high-quality semiconductor quantum-well sample. Monitoring the excitonic photoluminescence, we observe transient quenching of the $1s$ exciton emission, which we attribute to the terahertz-induced $1s$-to-$2p$ excitation. Simultaneously, a pronounced enhancement of the $2s$-exciton emission is observed, despite the $1s$-to-$2s$ transition being dipole forbidden. A microscopic many-body theory explains the experimental observations as a Coulomb-scattering mixing of the 2$s$ and 2$p$ states, yielding an effective terahertz transition between the 1$s$ and 2$s$ populations.Comment: 5 pages, 3 figure

Highly Conducting pi-Conjugated Molecular Junctions Covalently Bonded to Gold Electrodes

We measure electronic conductance through single conjugated molecules bonded to Au metal electrodes with direct Au-C covalent bonds using the scanning tunneling microscope based break-junction technique. We start with molecules terminated with trimethyltin end groups that cleave off in situ resulting in formation of a direct covalent sigma bond between the carbon backbone and the gold metal electrodes. The molecular carbon backbone used in this study consist of a conjugated pi-system that has one terminal methylene group on each end, which bonds to the electrodes, achieving large electronic coupling of the electrodes to the pi-system. The junctions formed with the prototypical example of 1,4-dimethylenebenzene show a conductance approaching one conductance quantum (G0 = 2e2/h). Junctions formed with methylene terminated oligophenyls with two to four phenyl units show a hundred-fold increase in conductance compared with junctions formed with amine-linked oligophenyls. The conduction mechanism for these longer oligophenyls is tunneling as they exhibit an exponential dependence of conductance with oligomer length. In addition, density functional theory based calculations for the Au-xylylene-Au junction show near-resonant transmission with a cross-over to tunneling for the longer oligomers.Comment: Accepted to the Journal of the American Chemical Society as a Communication

Palaeoenvironmental variability and carbon cycle perturbations during the Smithian-Spathian (Early Triassic) in Central Spitsbergen

The Early Triassic Smithian and Spathian time intervals are characterized by perturbations in the global carbon cycle, fluctuations in sea surface temperature, high turnover rates of marine nekton, and a change in terrestrial vegetation. Despite the importance of this time interval, comprehensive multiproxy investigations from Early Triassic high and middle latitude regions remain scarce due to the difficulty in accessing sections. The objective of this study is to increase our understanding of regional and local palaeoenvironmental and carbon cycle perturbations from a middle Smithian to late Spathian middle latitude section from Central Spitsbergen. Geochemical analyses show an increase in phosphorus and nitrogen just at and above the Smithian–Spathian boundary (SSB). High primary productivity led to increasingly anoxic conditions in bottom waters during the middle and late Spathian, enhancing the preservation of organic matter in the sediments. Anoxic conditions restrain phosphorus remineralization, allowing it to be recycled within the water column. This increase in anoxia is consistent with observations in other Arctic basins, demonstrating larger regional similarities in palaeoenvironmental conditions. The fluctuations in isostatic and eustatic sea levels affected organic carbon sequestration by regulating organic matter mineral interactions via the control of grain size within the sediment. This study demonstrates that local organic carbon sequestration in the Barents Sea shelf during the Spathian was influenced by a multitude of factors, including sedimentology, redox conditions, nutrient availability, and primary productivity. □ Vikinghøgda Formation, bulk rock geochemistry, particulate organic matter, extinction recovery, carbon isotopes, Stensiöfjellet Franziska R. Blattmann ✉ [[email protected]], Zoneibe A.S. Luz [[email protected]] and Torsten W. Vennemann [[email protected]], Institute of Earth Surface Dynamics, University of Lausanne, Quartier UNIL-Mouline, 1015 Lausanne, Switzerland; Elke Schneebeli-Hermann [[email protected]] and Hugo F.R. Bucher [[email protected]], Department of Palaeontology, University of Zürich, Karl-Schmid-Strasse 4, 8006 Zürich, Switzerland; Thierry Adatte [[email protected]], Institute of Earth Sciences, University of Lausanne, Quartier UNIL-Mouline, CH-1015 Lausanne, Switzerland; Christian Vérard [[email protected]], Section of Earth and Environmental Sciences, University of Geneva, Rue des Maraîchers 13, CH-1205 Geneva, Switzerland; Øyvind Hammer [[email protected]], Natural History Museum, University of Oslo, Pb. 1172 Blindern, 0318 Oslo, Norway; manuscript received on 08/08/2023; manuscript accepted on 02/02/2024; manuscript published on 20/06/2024 in Lethaia 57(2)

Snowmelt contribution to Arctic first-year ice ridge mass balance and rapid consolidation during summer melt

An assessment of potential groundwater areas in the Ifni basin, located in the western AntiAtlas range of Morocco, was conducted based on a multicriteria analytical approach that integrated a set of geomorphological and hydroclimatic factors influencing the availability of this resource. This approach involved the use of geographic information systems (GIS) and hierarchical analytical process (AHP) models. Different factors were classified and weighted according to their contribution to and impact on groundwater reserves. Their normalized weights were evaluated using a pairwise comparison matrix. Four classes of potentiality emerged: very high, high, moderate, and low, occupying 15.22%, 20.17%, 30.96%, and 33.65%, respectively, of the basin’s area. A groundwater potential map (GWPA) was validated by comparison with data from 134 existing water points using a receiver operating characteristic (ROC) curve. The AUC was calculated at 80%, indicating the good predictive accuracy of the AHP method. These results will enable water operators to select favorable sites with a high groundwater potential

Observation of squeezed light from one atom excited with two photons

Single quantum emitters like atoms are well-known as non-classical light sources which can produce photons one by one at given times, with reduced intensity noise. However, the light field emitted by a single atom can exhibit much richer dynamics. A prominent example is the predicted ability for a single atom to produce quadrature-squeezed light, with sub-shot-noise amplitude or phase fluctuations. It has long been foreseen, though, that such squeezing would be "at least an order of magnitude more difficult" to observe than the emission of single photons. Squeezed beams have been generated using macroscopic and mesoscopic media down to a few tens of atoms, but despite experimental efforts, single-atom squeezing has so far escaped observation. Here we generate squeezed light with a single atom in a high-finesse optical resonator. The strong coupling of the atom to the cavity field induces a genuine quantum mechanical nonlinearity, several orders of magnitude larger than for usual macroscopic media. This produces observable quadrature squeezing with an excitation beam containing on average only two photons per system lifetime. In sharp contrast to the emission of single photons, the squeezed light stems from the quantum coherence of photon pairs emitted from the system. The ability of a single atom to induce strong coherent interactions between propagating photons opens up new perspectives for photonic quantum logic with single emittersComment: Main paper (4 pages, 3 figures) + Supplementary information (5 pages, 2 figures). Revised versio

Sensitivity of the stress response function to packing preparation

A granular assembly composed of a collection of identical grains may pack under different microscopic configurations with microscopic features that are sensitive to the preparation history. A given configuration may also change in response to external actions such as compression, shearing etc. We show using a mechanical response function method developed experimentally and numerically, that the macroscopic stress profiles are strongly dependent on these preparation procedures. These results were obtained for both two and three dimensions. The method reveals that, under a given preparation history, the macroscopic symmetries of the granular material is affected and in most cases significant departures from isotropy should be observed. This suggests a new path toward a non-intrusive test of granular material constitutive properties.Comment: 15 pages, 11 figures, some numerical data corrected, to appear in J. Phys. Cond. Mat. special issue on Granular Materials (M. Nicodemi Editor

Improved count rate corrections for highest data quality with PILATUS detectors

A Monte Carlo simulation is presented, which computes the rate correction factors taking into account the detector settings and the time structure of the X-ray beam. The results show good agreement with experimentally determined correction factors