Study of Optical Response of Gold Nanoclusters Deposited on Polymer Substrates: Influence of in Situ Mechanical Deformation

Nanomaterials are the building blocks of today’s nanoscience and nanotechnology. Due to the distinct features of the nanomaterials, their utilization in the application sectors has increased. The field of metal nanocluster has been studied with increasing interest in the past few years. In this context, we study the influence of mechanical deformation on the optical transmittance of gold nanoclusters deposited on polymer substrate the polyurethane Clear Flex® 50 during in situ tensile test

Southern Europeans in France: Invisible Migrants?

France fared relatively well at the start of the current economic crisis, but has experienced low economic growth and high unemployment rates in the recent years. As a result it has been a less popular destination with Southern Europeans and EU migrants in general in search of economic opportunities. Although their numbers have increased and represent a growing proportion of recent flows to France, they remain low compared to numbers observed in Germany and the UK. Despite this statistical reality, EU mobility and more generally the role of the EU in economic and social policy have been at the forefront of debates in France since the start of the 2000s, thus well before the start of the crisis. These debates have focused on two populations – the Roma and posted workers – with both groups being portrayed as threats to the French welfare state. Although posted workers are not migrants, according to official EU definitions, their characteristics and experiences are similar to other groups of temporary migrant workers. Southern Europeans account for an increasing number of posted workers, and although they have not been the primary nationalities targeted in discussions concerning this issue, the debates and policy changes introduced in the recent years concern them as well. Moreover, we argue that the focusing of political debates on other populations in France has contributed to the relative invisibility of Southern European immigrants in this country

Primordial Black Holes: sirens of the early Universe

Primordial Black Holes (PBHs) are, typically light, black holes which can form in the early Universe. There are a number of formation mechanisms, including the collapse of large density perturbations, cosmic string loops and bubble collisions. The number of PBHs formed is tightly constrained by the consequences of their evaporation and their lensing and dynamical effects. Therefore PBHs are a powerful probe of the physics of the early Universe, in particular models of inflation. They are also a potential cold dark matter candidate.Comment: 21 pages. To be published in "Quantum Aspects of Black Holes", ed. X. Calmet (Springer, 2014

A Proposal for Multi-Constellation Advanced RAIM for Vertical Guidance

The GNSS environment will experience major changes in the coming years. GPS and GLONASS are undergoing modernization phases, while Galileo and Compass are currently in their deployment phase. When all these constellations are in their Full Operational Capability (FOC) state, there will be at least three times as many ranging sources than today. In addition, all of these GNSS core constellations will broadcast signals in the two frequency bands, L1/E1 and L5/E5. These signals will be available for civil aviation, allowing users to cancel the pseudorange errors due to the ionosphere. Many studies suggest that it could be possible to achieve global coverage of vertical guidance using multi-constellation, dual frequency Advanced Receiver Autonomous Integrity Monitoring (ARAIM). The benefits of ARAIM would include a reduced ground infrastructure (which would reduce the maintenance costs compared to current augmentation systems), a reduced dependency on any one GNSS core constellation, and, in general, lessen exposure to single points of failure. However, to achieve vertical guidance using ARAIM, it will not be sufficient to adapt the RAIM algorithms that are used for horizontal navigation. This is due to the increased level of safety required for vertical guidance compared to horizontal guidance. Therefore, ARAIM will require a careful faults and effects analysis. Because the integrity provision will be shared across service providers, it will be necessary to develop a common understanding in at least three domains: the navigation requirements, starting with LPV- 200; the airborne algorithm; and the threat model, comprised of both the nominal performance of the constellations and the fault modes. In this paper, we present a concept for the provision of integrity using multiple constellations with ARAIM and an Integrity Support Message (ISM). We will first propose an interpretation of the LPV-200 requirements in the ARAIM context. We will then propose a typical threat model for GNSS which includes both the nominal performance of the constellations and all the faults that need to be mitigated. These threats include both single satellite faults, multiple satellite faults, and constellation wide faults, one of them being the use or broadcast of erroneous Earth Orientation Parameters. We will show how the threats can be mitigated through the use of ground monitoring and the ISM in addition to the ARAIM subset position and residual test. Finally, we will give examples of multiple constellation configurations and performance providing worldwide coverage of LPV-200