Speckle noise reduction techniques for high-dynamic range imaging

High-dynamic range imaging from space in the visible, aiming in particular at the detection of terrestrial exoplanets, necessitates not only the use of a coronagraph, but also of adaptive optics to correct optical defects in real time. Indeed, these defects scatter light and give birth to speckles in the image plane. Speckles can be cancelled by driving a deformable mirror to measure and compensate wavefront aberrations. In a first approach, targeted speckle nulling, speckles are cancelled iteratively by starting with the brightest ones. This first method has demonstrated a contrast better than 1e9 in laboratory. In a second approach, zonal speckle nulling, the total energy of speckles is minimized in a given zone of the image plane. This second method has the advantage to tackle simultaneously all speckles from the targeted zone, but it still needs better experimental demonstration.Comment: 7 pages, 3 figures, in Optical techniques for direct imaging of exoplanets (a special issue of Comptes Rendus de Physique

Towards Large-Mode-Area fibers fabricated by the full vapor-phase SPCVD process

International audienceLarge-Mode-Area (LMA) fibers are key elements in modern high power fiber lasers operating at 1 µm. LMA fibers are highly ytterbium-doped and require a fine control of the core refractive index (RI) close to the silica level. These low RI have been achieved with multi-component materials elaborated using a full-vapor phase Surface Plasma Chemical Vapor Deposition (SPCVD) process, enabling the fabrication of large core diameter preforms (up to 4 millimeters). Following the technology demonstration, presented in Photonics West 2017, with results on 10/130 (core-to-clad diameters (in µm) ratio) fibers, this paper aims to present updated results obtained for double-clad 11/130, 20/130 and 20/400 LMA fibers, with numerical apertures at, respectively, 0.08 and 0.065. The study is based on aluminosilicate core material co-doped either with fluorine or phosphorus to achieve optimal radial RI tailoring. The fiber produced exhibit low background losses (<20dB/km at 1100nm) and high power conversion efficiencies, up to 74% for output powers of 100W limited by our test setup. The Gaussian beam quality has been evaluated using the M² measurement. Photodarkening behavior will be discussed for both fluorine and phosphorus-doped aluminosilicate materials and particularly the use of cerium as co-dopant. The SPCVD technology can indeed be used for the production of Yb-doped LMA fibers. Current development is now focused on other rare-earth doped fibers

Circulating adrenomedullin estimates survival and reversibility of organ failure in sepsis: the prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock-1 (AdrenOSS-1) study

Background: Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. Methods: AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. Results: Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p &lt; 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM &gt; 70 pg/ml upon admission than in those with bio-ADM ≤ 70 pg/ml. In patients with bio-ADM &gt; 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). Conclusions: AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. Trial registration: ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015

Observing the Forest Canopy with a New Ultra-Violet Compact Airborne Lidar

We have developed a new airborne UV lidar for the forest canopy and deployed it in the Landes forest (France). It is the first one that: (i) operates at 355 nm for emitting energetic pulses of 16 mJ at 20 Hz while fulfilling eye-safety regulations and (ii) is flown onboard an ultra-light airplane for enhanced flight flexibility. Laser footprints at ground level were 2.4 m wide for a flying altitude of 300 m. Three test areas of ∼500 × 500 m2 with Maritime pines of different ages were investigated. We used a threshold method adapted for this lidar to accurately extract from its waveforms detailed forest canopy vertical structure: canopy top, tree crown base and undergrowth heights. Good detection sensitivity enabled the observation of ground returns underneath the trees. Statistical and one-to-one comparisons with ground measurements by field foresters indicated a mean absolute accuracy of ∼1 m. Sensitivity tests on detection threshold showed the importance of signal to noise ratio and footprint size for a proper detection of the canopy vertical structure. This UV-lidar is intended for future innovative applications of simultaneous observation of forest canopy, laser-induced vegetation fluorescence and atmospheric aerosols

An innovative integral field unit upgrade with 3D-printed micro-lenses for the RHEA at Subaru

In the new era of Extremely Large Telescopes (ELTs) currently under construction, challenging requirements drive spectrograph designs towards techniques that efficiently use a facility's light collection power. Operating in the single-mode (SM) regime, close to the diffraction limit, reduces the footprint of the instrument compared to a conventional high-resolving power spectrograph. The custom built injection fiber system with 3D-printed micro-lenses on top of it for the replicable high-resolution exoplanet and asteroseismology spectrograph at Subaru in combination with extreme adaptive optics of SCExAO, proved its high efficiency in a lab environment, manifesting up to ~77% of the theoretical predicted performance

Jules Romains' Vision of a United Europe in Interwar France: Legacy and Ambiguities

The interwar period in Europe was characterised by a multi-faceted movement in favour of European integration. After the slaughter of the First World War, many intellectuals, writers, industrialists and politicians brought the idea of European unity to the fore and engaged in various actions, from setting up organisations to lobbying governments, to promote the unification of Europe. Much research has been carried out on the leading figures of these pro-European activities but amongst the wealth of this period other actors have tended to be forgotten. Such is the case with the French writer Jules Romains, who not only coined “Europeanism”, the word that would define the whole movement in favour of Europe, but who also actively participated in promoting a united Europe. This article seeks to introduce and discuss Romains’ ideas on Europe. It will demonstrate that his vision was very coherent within the framework of his Unanimist philosophy but was undermined by serious ambiguities. It will also demonstrate that his ideas are of great interest for what they reveal about the interwar period in France and Europe, what they bring to the genealogy of the European project, as set up after the Second World War, and for the ambiguities at the core of his concept of Europe, which are still very much at the heart of many of today’s debates about the European Union

Chemical and physical properties of Amazonian aerosol particles

- ZUSAMMENFASSUNG:Die vorliegende Dissertation befasst sich mit der Bestimmung der chemischen und physikalischen Eigenschaften von Aerosolpartikeln im Amazonasbecken, die während Zeiten mit Biomasseverbrennung und bei Hintergrundbedingungen bestimmt wurden. Die Messungen wurden während zwei Kampagnen im Rahmen des europäischen Beitrags zum LBA-EUSTACH Experiment in Amazonien. Die Daten umfassen Messungen der Anzahlkonzentrationen, Größenverteilungen, optischen Eigenschaften sowie Elementzusammensetzungen und Kohlenstoffgehalte der gesammelten Aerosole. Die Zusammensetzung des Aerosols wies auf folgende drei Quellen hin: natürlichen biogenen, Mineralstaub, und pyrogenes Aerosol. Aller drei Komponenten trugen signifikant zur Extinktion des Sonnenlichts bei. Insgesamt ergab sich eine Steigerung der Meßwerte um ca. das Zehnfache während der Trockenzeit im Vergleich zur Regenzeit, was auf eine massive Einbringung von Rauchpartikeln im Submikrometerbereich in die Atmosphäre während der Trockenzeit zurückzuführen ist. Dementsprechend sank die Einzelstreualbedo von ca. 0,97 auf 0,91. Der Brechungsindex der Aerosolpartikel wurde mit einer neuen iterative Methoden, basierend auf der Mie-Theorie berechnet. Es ergaben sich durchschnittliche Werte von 1,42 0,006i für die Regenzeit und 1,41 0,013i für die Trockenperiode. Weitere klimatisch relevante Parameterergaben für Hintergrundaerosole und für Aerosole aus Biomasseverbrennung folgende Werte: Asymmetrieparameter von 0,63 ± 0,02 bzw. 0,70 ± 0,03 und Rückstreuungsverhältnisse von 0,12 ± 0,01 bzw. 0,08 ± 0,01. Diese Veränderungen haben das Potential, das regionale und globale Klima über die Variierung der Extinktion der Sonneneinstrahlung als auch der Wolkeneigenschaften zu beeinflussen.- English Summary:This dissertation focuses on the determination of the chemical and physical properties of aerosol particles over the Amazon basin under background and biomass burning conditions. The measurements were made during two campaigns as part of the European contribution to the LBA-EUSTACH international project.The data set includes measurements of aerosol particle number concentrations, size distributions, optical properties, as well as the elemental and carbonaceous content of the aerosol. Three components were found to comprise the bulk of the total aerosol loading during both seasons (natural biogenic, soil dust, and pyrogenic aerosols), which all contributed significantly to light extinction. Overall, the measured parameters showed a roughly ten-fold increase in from the wet to the biomass-burning-influenced dry season. Correspondingly, the single-scattering albedo decreased from ca. 0.97 to 0.91. The refractive index of the aerosol particles was calculated using a new iterative method based on Mie theory, yielding averaged values of 1.42 0.006i and 1.41 0.013i for the wet and dry seasons, respectively. Other climatically relevant parameters like the asymmetry parameter and the backscattered fraction were also derived from the Mie calculations. The potential exists for these changes to impact on regional and global climate through changes to the extinction of solar radiation as well as the alteration of cloud properties

Les mémoires des bombardements alliés en Moyenne et Basse Vallée-du-Rhône

The Allied bombings of 1944 in the Middle and Lower Rhône Valley have had a strong impact on territories and societies. However, their memories are little present in the national narrative. To explain this contradiction, we undertook a systematic census of memory markers in public space and in private places. We then undertook to analyze them, in order to understand their genesis, to determine who their initiators were, and to establish the possible issues they raise. Once this corpus was established, we were able to establish that memories of the bombings are omnipresent in everyday space, but that they are often ignored by the people around them. We were thus able to determine that the transmission of these memories first took place within the family context, before taking place in the collective memory for about twenty years now. A final process emerged in the context of the 80th anniversary of the bombings, marked by the passage from memory to History, with the promotion of tourism for these events.Les bombardements alliés de l'année 1944 en Moyenne et Basse Vallée-du-Rhône ont fortement impacté les territoires et les sociétés. Pourtant, leurs mémoires sont peu présentes dans le récit national. Pour expliquer cette contradiction, nous avons entrepris un recensement systématique des marqueurs de mémoire dans l'espace public et dans des lieux privés. Nous avons ensuite entrepris de les analyser, afin de comprendre quelle a été leur genèse, de déterminer quels en ont été les initiateurs, et établir les éventuels enjeux dont ils sont porteurs. Une fois ce corpus constitué, nous avons pu établir que les mémoires des bombardements sont omniprésentes dans l'espace quotidien, mais qu'elles sont souvent ignorées par les personnes qui les côtoient. Nous avons ainsi pu déterminer que la transmission de ces mémoires s'est d'abord faite au sein du cadre familial, avant de prendre place dans la mémoire collective depuis une vingtaine d'années. Un dernier processus s'est fait jour dans le cadre du 80ème anniversaire des bombardements, marqué par le passage de la mémoire à l'Histoire, avec une mise en tourisme de ces événements

Les mémoires des bombardements alliés en Moyenne et Basse Vallée-du-Rhône

The Allied bombings of 1944 in the Middle and Lower Rhône Valley have had a strong impact on territories and societies. However, their memories are little present in the national narrative. To explain this contradiction, we undertook a systematic census of memory markers in public space and in private places. We then undertook to analyze them, in order to understand their genesis, to determine who their initiators were, and to establish the possible issues they raise. Once this corpus was established, we were able to establish that memories of the bombings are omnipresent in everyday space, but that they are often ignored by the people around them. We were thus able to determine that the transmission of these memories first took place within the family context, before taking place in the collective memory for about twenty years now. A final process emerged in the context of the 80th anniversary of the bombings, marked by the passage from memory to History, with the promotion of tourism for these events.Les bombardements alliés de l'année 1944 en Moyenne et Basse Vallée-du-Rhône ont fortement impacté les territoires et les sociétés. Pourtant, leurs mémoires sont peu présentes dans le récit national. Pour expliquer cette contradiction, nous avons entrepris un recensement systématique des marqueurs de mémoire dans l'espace public et dans des lieux privés. Nous avons ensuite entrepris de les analyser, afin de comprendre quelle a été leur genèse, de déterminer quels en ont été les initiateurs, et établir les éventuels enjeux dont ils sont porteurs. Une fois ce corpus constitué, nous avons pu établir que les mémoires des bombardements sont omniprésentes dans l'espace quotidien, mais qu'elles sont souvent ignorées par les personnes qui les côtoient. Nous avons ainsi pu déterminer que la transmission de ces mémoires s'est d'abord faite au sein du cadre familial, avant de prendre place dans la mémoire collective depuis une vingtaine d'années. Un dernier processus s'est fait jour dans le cadre du 80ème anniversaire des bombardements, marqué par le passage de la mémoire à l'Histoire, avec une mise en tourisme de ces événements