Apodized pupil Lyot coronagraphs for arbitrary apertures. V. Hybrid Shaped Pupil designs for imaging Earth-like planets with future space observatories

We introduce a new class of solutions for Apodized Pupil Lyot Coronagraphs (APLC) with segmented aperture telescopes to remove broadband diffracted light from a star with a contrast level of $10^{10}$. These new coronagraphs provide a key advance to enabling direct imaging and spectroscopy of Earth twins with future large space missions. Building on shaped pupil (SP) apodization optimizations, our approach enables two-dimensional optimizations of the system to address any aperture features such as central obstruction, support structures or segment gaps. We illustrate the technique with a design that could reach $10^{10}$ contrast level at 34\,mas for a 12\,m segmented telescope over a 10\% bandpass centered at a wavelength $\lambda_0=$500\,nm. These designs can be optimized specifically for the presence of a resolved star, and in our example, for stellar angular size up to 1.1\,mas. This would allow probing the vicinity of Sun-like stars located beyond 4.4\,pc, therefore fully retiring this concern. If the fraction of stars with Earth-like planets is \eta_{\Earth}=0.1, with 18\% throughput, assuming a perfect, stable wavefront and considering photon noise only, 12.5 exo-Earth candidates could be detected around nearby stars with this design and a 12\,m space telescope during a five-year mission with two years dedicated to exo-Earth detection (one total year of exposure time and another year of overheads). Our new hybrid APLC/SP solutions represent the first numerical solution of a coronagraph based on existing mask technologies and compatible with segmented apertures, and that can provide contrast compatible with detecting and studying Earth-like planets around nearby stars. They represent an important step forward towards enabling these science goals with future large space missions.Comment: 9 pages, 6 figures, ApJ accepted on 01/04/201

High contrast imaging with an arbitrary aperture: active correction of aperture discontinuities: fundamental limits and practical trade-offs

We present a new method to achieve high-contrast images using segmented and/or on-axis telescopes. Our approach relies on using two sequential Deformable Mirrors to compensate for the large amplitude excursions in the telescope aperture due to secondary support structures and / or segment gaps. We solve the highly non-linear Monge-Ampere equation that is the fundamental equation describing the physics of phase induced amplitude modulation. We determine the optimum configuration for our two sequential Deformable Mirror system and show that high-throughput and high contrast solutions can be achieved using realistic surface deformations that are accessible using existing technologies. We name this process Active Compensation of Aperture Discontinuities (ACAD). We show that for geometries similar to JWST, ACAD can attain at least 10-7 in contrast and an order of magnitude higher for future Extremely Large Telescopes, even when the pupil features a "missing segment" . Because the converging non-linear mappings resulting from our Deformable Mirror shapes damps near-field diffraction artifacts in the vicinity of the discontinuities this solution is particularly appealing in terms of spectral bandwidth. We present preliminary results that illustrate the performances of ACAD in the presence of diffraction for apertures for with secondary support structures of varying width and argue that the ultimate contrast achieved can by combining ACAD with modern wavefront control algorithms

High-contrast imager for Complex Aperture Telescopes (HiCAT): 1. Testbed design

Searching for nearby habitable worlds with direct imaging and spectroscopy will require a telescope large enough to provide angular resolution and sensitivity to planets around a significant sample of stars. Segmented telescopes are a compelling option to obtain such large apertures. However, these telescope designs have a complex geometry (central obstruction, support structures, segmentation) that makes high-contrast imaging more challenging. We are developing a new high-contrast imaging testbed at STScI to provide an integrated solution for wavefront control and starlight suppression on complex aperture geometries. We present our approach for the testbed optical design, which defines the surface requirements for each mirror to minimize the amplitude-induced errors from the propagation of out-of-pupil surfaces. Our approach guarantees that the testbed will not be limited by these Fresnel propagation effects, but only by the aperture geometry. This approach involves iterations between classical ray-tracing optical design optimization, and end-to-end Fresnel propagation with wavefront control (e.g. Electric Field Conjugation / Stroke Minimization). The construction of the testbed is planned to start in late Fall 2013.Comment: Proc. of the SPIE 8864, 10 pages, 3 figures, Techniques and Instrumentation for Detection of Exoplanets V

High contrast imaging with an arbitrary aperture: active correction of aperture discontinuities: fundamental limits and practical trade-offs

We present a new method to achieve high-contrast images using segmented and/or on-axis telescopes. Our approach relies on using two sequential Deformable Mirrors to compensate for the large amplitude excursions in the telescope aperture due to secondary support structures and / or segment gaps. We solve the highly non-linear Monge-Ampere equation that is the fundamental equation describing the physics of phase induced amplitude modulation. We determine the optimum configuration for our two sequential Deformable Mirror system and show that high-throughput and high contrast solutions can be achieved using realistic surface deformations that are accessible using existing technologies. We name this process Active Compensation of Aperture Discontinuities (ACAD). We show that for geometries similar to JWST, ACAD can attain at least 10-7 in contrast and an order of magnitude higher for future Extremely Large Telescopes, even when the pupil features a "missing segment" . Because the converging non-linear mappings resulting from our Deformable Mirror shapes damps near-field diffraction artifacts in the vicinity of the discontinuities this solution is particularly appealing in terms of spectral bandwidth. We present preliminary results that illustrate the performances of ACAD in the presence of diffraction for apertures for with secondary support structures of varying width and argue that the ultimate contrast achieved can by combining ACAD with modern wavefront control algorithms

Caractéristiques et devenir des patients atteints de maladies systémiques admis en réanimation (étude rétrospective de 145 patients sur 10 ans (1996-2006))

Il existe peu de données épidémiologiques récentes sur les patients atteints de maladies systémiques admis en réanimation. Nous rapportons le devenir et les facteurs pronostiques de ces patients dans une étude rétrospective et appariée sur 10 ans. Les données démographiques, le motif d hospitalisation, les index de Charlson et de Knaus, les scores de gravité (APACHE II, SAPS II, SAPS 3) et de défaillance d organe (LOD et SOFA) sont colligés. Nous analysons la mortalité hospitalière et à un ana. Les facteurs pronostiques sont évalués en analyse uni et multivariée. Pour rechercher l existence d une effet maladie nous réalisons un appariement 3/1 sur l âge, le sexe et le SAPS II. Nous analysons 145 patients dont les motifs d hospitalisation sont une détresse respiratoire (45%), un choc septique (15%) ou un trouble neurologique (13%). Dans 43% des cas, une infection est associée à l admission. La mortalité hospitalière est de 33%. Les facteurs prédictifs de mortalité intrahospitalière sont l âge, l admission pour infection (OR=3.7), les scores de de Charlson >2 (OR=5.1) et de Knaus C/D (OR=4.4) les scores généralistes et de défaillances d organes. En analyse multivariée le SAPS 3 et sepsis nosocomial sont des facteurs pronostiques. L analyse multivariée cas/témoins montre une surmortalité des cas (OR=3.3) et un risque infectieux accru (OR=2). La moralité des patients atteints de maladies systémiques admis en réanimation s améliorer au cours du temps, et il semble exister ici un effet maladie . En outre, ces patients ont une susceptibilité accrue aux infections qui jouent un rôle pronostique car elles représentent la première cause de mortalité.PARIS6-Bibl.Pitié-Salpêtrie (751132101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Severe and prolonged neurologic toxicity following subcutaneous chlorpyrifos self-administration: A case report

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Ultrasound assessment of lung aeration loss during a successful weaning trial predicts postextubation distress*.

Lung ultrasound determination of aeration changes during a successful spontaneous breathing trial may accurately predict postextubation distress

Active correction of aperture discontinuities (ACAD) for space telescope pupils: a parametic analysis

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