Image transmission through a stable paraxial cavity

We study the transmission of a monochromatic "image" through a paraxial cavity. Using the formalism of self-transform functions, we show that a transverse degenerate cavity transmits the self-transform part of the image, with respect to the field transformation over one round-trip of the cavity. This formalism gives a new insight on the understanding of the behavior of a transverse degenerate cavity, complementary to the transverse mode picture. An experiment of image transmission through a hemiconfocal cavity show the interest of this approach.Comment: submitted to Phys. Rev.

Interactions between financial incentives and health in the early retirement decision

We present a theory of the relation between health and retirement that generates testable predictions regarding the interaction of health, wealth and financial incentives in retirement decisions. The theory predicts (i) that wealthier individuals (compared to poorer individuals) are more likely to retire for health reasons (affordability proposition), and (ii) that health problems make older workers more responsive to financial incentives encouraging retirement (reinforcement proposition). We test these predictions using administrative data on older employees in the Dutch healthcare sector for whom we link adverse health events, proxied by unanticipated hospitalizations, to information on retirement decisions and actual incentives from administrative records of the pension funds. Exploiting unexpected health shocks and quasi-exogenous variation in financial incentives for retirement due to reforms, we account for the endogeneity of health and financial incentives. Making use of the actual individual pension rights diminishes downward bias in estimates of the effect of pension incentives. We find support for our affordability and reinforcement propositions. Both propositions require the benefits function to be convex, as in our data. Our theory and empirical findings highlight the importance of assessing financial incentives for their potential reinforcement of health shocks and point to the possibility that differences in responses to financial incentives and health shocks across countries may relate to whether the benefit function is concave or convex

Stairs detection with odometry-aided traversal from a wearable RGB-D camera

Stairs are one of the most common structures present in human-made scenarios, but also one of the most dangerous for those with vision problems. In this work we propose a complete method to detect, locate and parametrise stairs with a wearable RGB-D camera. Our algorithm uses the depth data to determine if the horizontal planes in the scene are valid steps of a staircase judging their dimensions and relative positions. As a result we obtain a scaled model of the staircase with the spatial location and orientation with respect to the subject. The visual odometry is also estimated to continuously recover the current position and orientation of the user while moving. This enhances the system giving the ability to come back to previously detected features and providing location awareness of the user during the climb. Simultaneously, the detection of the staircase during the traversal is used to correct the drift of the visual odometry. A comparison of results of the stair detection with other state-of-the-art algorithms was performed using public dataset. Additional experiments have also been carried out, recording our own natural scenes with a chest-mounted RGB-D camera in indoor scenarios. The algorithm is robust enough to work in real-time and even under partial occlusions of the stair

Improving control of quadrotors carrying a manipulator arm

International audienc

A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass m c sin i c = 5.8 ± 1.9 M ⊕ and orbital period P c = 5.21 - 0.22 + 0.26 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.Peer reviewedFinal Published versio

Multiwavelength study of the G345.5+1.5 region

Context. The star formation process requires the dust and gas present in the Milky Way to self-assemble into dense reservoirs ofneutral material where the new generation of stars will emerge. Star-forming regions are usually studied in the context of Galacticsurveys, but dedicated observations are sometimes needed when the study reaches beyond the survey area.Aims. A better understanding of the star formation process in the Galaxy can be obtained by studying several regions. This allowsincreasing the sample of objects (clumps, cores, and stars) for further statistical works and deeper follow-up studies. Here, we studiedthe G345.5+1.5 region, which is located slightly above the Galactic plane, to understand its star formation properties.Methods. We combined the Large Apex BOlometer CAmera (LABOCA) and 12 CO(4−3) transition line (NANTEN2) observationscomplemented with the Hi-GAL and Spitzer-GLIMPSE surveys to study the star formation toward this region. We used the Clumpfindalgorithm to extract the clumps from the 870 μm and 12 CO(4−3) data. Radio emission at 36 cm was used to estimate the number ofH ii regions and to remove the contamination from the free-free emission at 870 μm. We employed color-color diagrams and spectralenergy distribution (SED) slopes to distinguish between prestellar and protostellar clumps. We studied the boundedness of the clumpsthrough the virial parameter. Finally, we estimated the star formation efficiency (SFE) and star formation rate (SFR) of the region andused the Schmidt-Kennicutt diagram to compare its ability to form stars with other regions of the Galactic plane.Results. Of the 13 radio sources that we found using the MGPS-2 catalog, 7 are found to be associated with H ii regions correspondingto late-B or early-O stars. We found 45 870 μm clumps with diameters between 0.4 and 1.2 pc and masses between 43 M and3923 M , and 107 12 CO clumps with diameters between 0.4 pc and 1.3 pc and masses between 28 M and 9433 M . More than 50%of the clumps are protostellar and bounded and are able to host (massive) star formation. High SFR and SFR density (ΣS FR ) valuesare associated with the region, with an SFE of a few percent.Conclusions. With submillimeter, CO transition, and short-wavelength infrared observations, our study reveals a population of mas-sive stars, protostellar and bound starless clumps, toward G345.5+1.5. This region is therefore actively forming stars, and its locationin the starburst quadrant of the Schmidt-Kennicutt diagram is comparable to other star-forming regions found within the Galacticplane.Fil: Figueira, M.. Aix Marseille Universite; FranciaFil: Lopez Calderon, C.. Joint Alma Observatory; ChileFil: Bronfman, L.. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas; ChileFil: Zavagno, A.. Aix Marseille Universite; FranciaFil: Hervias Caimapo C.. University of Manchester; Reino UnidoFil: Duronea, Nicolas Urbano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Åke Nyman, Lars. Joint Alma Observatory; Chil