High-availability displacement sensing with multi-channel self mixing interferometry

Laser self-mixing is in principle a simple and robust general purpose interferometric method, with the additional expressivity which results from nonlinearity. However, it is rather sensitive to unwanted changes in target reflectivity, which often hinders applications with non-cooperative targets. Here we analyze experimentally a multi-channel sensor based on three independent self-mixing signals processed by a small neural network. We show that it provides high-availability motion sensing, robust not only to measurement noise but also to complete loss of signal in some channels. As a form of hybrid sensing based on nonlinear photonics and neural networks, it also opens perspectives for fully multimodal complex photonics sensing

Dissipative phase solitons in semiconductor lasers

We experimentally demonstrate the existence of non dispersive solitary waves associated with a 2$\pi$ phase rotation in a strongly multimode ring semiconductor laser with coherent forcing. Similarly to Bloch domain walls, such structures host a chiral charge. The numerical simulations based on a set of effective Maxwell-Bloch equations support the experimental evidence that only one sign of chiral charge is stable, which strongly affects the motion of the phase solitons. Furthermore, the reduction of the model to a modified Ginzburg Landau equation with forcing demonstrates the generality of these phenomena and exposes the impact of the lack of parity symmetry in propagative optical systems.Comment: 5 pages, 5 figure

Raising the stimulated Brillouin scattering threshold power by longitudinal compression gradient in a fiber amplifier

We demonstrate and analyse a novel approach to enhance the threshold power of stimulated Brillouin scattering (SBS) in optical fibers, using a longitudinal compressive strain gradient. We derive analytical expressions for the power spectral density of the backscattered Stokes wave in the general case of passive and amplifying optical fibers, by considering the strain and optical power distributions. Our method provides an accurate prediction of the SBS gain spectrum, that we illustrate with a quantitative comparison between measurements and calculations of the SBS Stokes spectra, before and after applying the compression gradient. Our experimental results demonstrate the successful enhancement of the SBS threshold power by a factor of about 3 for the passive fiber and 2 for the amplifying fiber. The enhancement that we manage to calculate in the case of the passive fiber is in perfect agreement with the experimental result

Le siège de Saint-Sébastien en 1813 avec 1 croquis dans le texte

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 2007CCFr, 18/02/2008, da como fecha probable para esta éd. 190

Laboratory Geotechnical Investigations on Five Silty Soils Sampled Along the Banks of the Lubumbashi River/Haut-Katanga/DR Congo

peer reviewedAn adequate design of port structures along waterways requires a good knowledge of the geotechnical properties of the surrounding soils. This study aims to characterize the geotechnical laboratory properties of alluvial soils along the Lubumbashi river (section between the Tshombe and Tshondo bridges, approximately 3 km long) in the city of Lubumbashi, province of Haut Katanga in DR Congo. To meet this objective, five sampling zones were selected from which samples were taken with a hand auger and various geotechnical laboratory tests were performed. Identification tests reveal that the tested soils have low to moderate plasticity and are in the range of sandy silt to silty sand with a low fraction of clay particles, essentially inactive. Oedometric compression tests reveal that the soils in place are (moderately) compressible. The consolidated undrained (CU) triaxial compression and direct shear tests indicate effective values of internal friction angle and negligible drained cohesion that, are consistent for this kind of soil. In the end, the compressibility and strength parameters of the five tested soils are correlated with their plasticity index, showing a decrease in the shear strength and an increase in the compressibility when the plasticity index increase

Molecular basis of African yam domestication: Analyses of selection point to root development, starch biosynthesis, and photosynthesis related genes

Background: After cereals, root and tuber crops are the main source of starch in the human diet. Starch biosynthesis was certainly a significant target for selection during the domestication of these crops. But domestication of these root and tubers crops is also associated with gigantism of storage organs and changes of habitat. Results: We studied here, the molecular basis of domestication in African yam, Dioscorea rotundata. The genomic diversity in the cultivated species is roughly 30% less important than its wild relatives. Two percent of all the genes studied showed evidences of selection. Two genes associated with the earliest stages of starch biosynthesis and storage, the sucrose synthase 4 and the sucrose-phosphate synthase 1 showed evidence of selection. An adventitious root development gene, a SCARECROW-LIKE gene was also selected during yam domestication. Significant selection for genes associated with photosynthesis and phototropism were associated with wild to cultivated change of habitat. If the wild species grow as vines in the shade of their tree tutors, cultivated yam grows in full light in open fields. Conclusions: Major rewiring of aerial development and adaptation for efficient photosynthesis in full light characterized yam domestication. (Résumé d'auteur

Measures de vent 3D avec le lidar Doppler coherent Live à bord d'un avion

International audienceA three-dimensional (3D) wind profiling Lidar, based on the latest high power 1.5 µm fiber laser development at Onera, has been successfully flown on-board a SAFIRE (Service des Avions Français Instrumentés pour la Recherche en Environnement) ATR42 aircraft. The Lidar called LIVE (LIdar VEnt) is designed to measure wind profiles from the aircraft down to ground level, with a horizontal resolution of 3 km, a vertical resolution of 100 m and a designed accuracy on each three wind vector components better than 0.5 m.s −1. To achieve the required performance, LIVE Lidar emits 410 µJ laser pulses repeating at 14 KHz with a duration of 700 ns and uses a conical scanner of 30 • total opening angle and a full scan time of 17 s.Un lidar vent 3D, basé sur le dernier développement de laser à fibre de 1,5 µm à haute puissance de l’ONERA a été testé avec succès à bord d’un avion SAFIRE ATR42. Le lidar appelé LIVE est conçu pour mesurer les profils de vent de l’avion jusqu'au sol, avec une résolution horizontale de 3 km, une résolution verticale de 100 m et une précision calculée supérieure à 0,5 m / s pour chaque composante du vecteur du vent

Emergency department outcome of elderly patients assisted by professional home services, the EPIGER study.

BACKGROUND: For the elderly population living at home, the implementation of professional services tends to mitigate the effect of loss of autonomy and increases their quality of life. While helping in avoiding social isolation, home services could also be associated to different healthcare pathways. For elderly patients, Emergency Departments (EDs) are the main entrance to hospital where previous loss of autonomy is associated to worst hospital outcomes. Part of elderly patients visiting EDs are still admitted to hospital for having difficulties coping at home without presenting any acute medical issue. There is a lack of data concerning elderly patients visiting EDs assisted by home services. Our aim was to compare among elderly patients visiting ED those assisted by professional home services to those who do not in terms of emergency resources' use and patients' outcome. METHODS: A multicenter, prospective cohort study was performed in 124 French EDs during a 24-h period on March 2016.Consecutive patients living at home aged ≥80 years were included. The primary objective was to assess the risk of mortality for patients assisted by professional home services vs. those who were not. Secondary objectives included admission rate and specific admission rate for "having difficulties coping at home". The primary endpoint was in-hospital mortality. Cox proportional-hazards regression model was used to test the association between professional home services and the primary endpoint. Multi variables logistic regressions were performed to assess secondary endpoints. RESULTS: One thousand one hundred sixty-eight patients were included, median age 86(83-89) years old,32% were assisted by professional home services. The overall in-hospital mortality rate was 7%. Assisted patients had more investigations performed. Home services were not associated with increased in-hospital mortality (HR = 1.34;95%CI [0.68-2.67]), nor with the admission rate (OR = 0.92;95%CI [0.65-1.30]). Assisted patients had a lower risk of being admitted for "having difficulties coping at home" (OR = 0.59;95%CI [0.38-0.92]). CONCLUSION: Professional home services which assist one-third of elderly patients visiting EDs, were not associated to lower in-hospital mortality or to an increased admission rate. Assisted patients were associated to a lower risk of being admitted for «having difficulties coping at home».Professional home services could result in avoiding some admissions and their corollary complications. TRIAL REGISTRATION: Clinicaltrial.gov - NCT02900391 , 09/14/2016, retrospectively registered

Ecological Aspects of Tabanids (Diptera: Tabanidae) in a Gabonese Cattle Ranch

To embark on an anti-vectorial fight against mechanical vectors of animal trypanosomosis, investigations were undertaken in order to determine the abundance, species diversity and daily activity of tabanids in a cattle ranch in Gabon. The nzi and vavoua traps were used to catch tabanids in three divisions of this ranch. In this study, 616 tabanids were captured: 349 (56.66%) in Division 1, 226 (36.69%) in Division 2 and 41 (6.66%) in Division 3. In the first Division, T. taeniola was the most abundant species with an Apparent Density (ADT) of 2.2, followed by H. pluvialis (ADT = 1.05). In the second Division, H. pluvialis was most abundant with ADT of 1.6, followed by T. taeniola (ADT = 0.38). In the last Division, the most abundant species was H. pluvialis (ADT = 0.15). Comparing the relative abundance of catches with sites (Divisions), we realized that there was no statistically significant difference in catches with trapping sites. It was noticed that Division 3 recorded the highest diversity index values. We realized that the nzi trap recorded higher tabanid catches than the vavoua trap. The diurnal activity rhythm of the most frequent species encountered slightly differed with prospection sites