The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph currently in manufacturing, assembly and integration phase. MUSE has a field of 1x1 ...arcmin2 sampled at 0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The instrument is a large assembly of 24 identical high performance integral field units, each one composed of an advanced image slicer, a spectrograph and a 4kx4k detector. In this paper we review the progress of the manufacturing and report the performance achieved with the first integral field unit.
The nature of circumstellar envelopes (CSE) around Cepheids is still a matter of debate. The physical origin of their infrared (IR) excess could be either a shell of ionized gas, or a dust envelope, ...or both. This study aims at constraining the geometry and the IR excess of the environment of the long-period Cepheid \(\ell\) Car (P=35.5 days) at mid-IR wavelengths to understand its physical nature. We first use photometric observations in various bands and Spitzer Space Telescope spectroscopy to constrain the IR excess of \(\ell\) Car. Then, we analyze the VLTI/MATISSE measurements at a specific phase of observation, in order to determine the flux contribution, the size and shape of the environment of the star in the L band. We finally test the hypothesis of a shell of ionized gas in order to model the IR excess. We report the first detection in the L band of a centro-symmetric extended emission around l Car, of about 1.7\(R_\star\) in FWHM, producing an excess of about 7.0\% in this band. In the N band, there is no clear evidence for dust emission from VLTI/MATISSE correlated flux and Spitzer data. On the other side, the modeled shell of ionized gas implies a more compact CSE (\(1.13\pm0.02\,R_\star\)) and fainter (IR excess of 1\% in the L band). We provide new evidences for a compact CSE of \(\ell\) Car and we demonstrate the capabilities of VLTI/MATISSE for determining common properties of CSEs. While the compact CSE of \(\ell\) Car is probably of gaseous nature, the tested model of a shell of ionized gas is not able to simultaneously reproduce the IR excess and the interferometric observations. Further Galactic Cepheids observations with VLTI/MATISSE are necessary for determining the properties of CSEs, which may also depend on both the pulsation period and the evolutionary state of the stars.
Context. The inner few au region of planet-forming disks is a complex environment. High angular resolution observations have a key role in understanding the disk structure and the dynamical processes ...at work. Aims. In this study we aim to characterize the mid-infrared brightness distribution of the inner disk of the young intermediate-mass star HD 163296, from VLTI/MATISSE observations. Methods. We use geometric models to fit the data. Our models include a smoothed ring, a flat disk with inner cavity, and a 2D Gaussian. The models can account for disk inclination and for azimuthal asymmetries as well. We also perform numerical hydro-dynamical simulations of the inner edge of the disk. Results. Our modeling reveals a significant brightness asymmetry in the L-band disk emission. The brightness maximum of the asymmetry is located at the NW part of the disk image, nearly at the position angle of the semimajor axis. The surface brightness ratio in the azimuthal variation is \(3.5 \pm 0.2\). Comparing our result on the location of the asymmetry with other interferometric measurements, we confirm that the morphology of the \(r<0.3\) au disk region is time-variable. We propose that this asymmetric structure, located in or near the inner rim of the dusty disk, orbits the star. For the physical origin of the asymmetry, we tested a hypothesis where a vortex is created by Rossby wave instability, and we find that a unique large scale vortex may be compatible with our data. The half-light radius of the L-band emitting region is \(0.33\pm 0.01\) au, the inclination is \({52^\circ}^{+5^\circ}_{-7^\circ}\), and the position angle is \(143^\circ \pm 3^\circ\). Our models predict that a non-negligible fraction of the L-band disk emission originates inside the dust sublimation radius for \(\mu\)m-sized grains. Refractory grains or large (\(\gtrsim 10\ \mu\)m-sized) grains could be the origin for this emission.
CRIRES, the ESO high resolution infrared spectrometer, is a unique instrument which allows astronomers to access a parameter space which up to now was largely uncharted. In its current setup, it ...consists of a single-order spectrograph providing long-slit, single-order spectroscopy with resolving power up to R=100,000 over a quite narrow spectral range. This has resulted in sub-optimal efficiency and use of telescope time for all the scientific programs requiring broad spectral coverage of compact objects (e.g. chemical abundances of stars and intergalactic medium, search and characterization of extra-solar planets). To overcome these limitations, a consortium was set-up for upgrading CRIRES to a cross-dispersed spectrometer, called CRIRES+. This paper presents the updated optical design of the crossdispersion module for CRIRES+. This new module can be mounted in place of the current pre-disperser unit. The new system yields a factor of >10 increase in simultaneous spectral coverage and maintains a quite long slit (10"), ideal for observations of extended sources and for precise sky-background subtraction.
The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph ...will be installed at the Combined-Coudé Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coudé trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial-velocity precision to reach the 10 cm/s level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astrophysics that require precision and sensitivity. The main scientific drivers are the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M-dwarfs and the analysis of the variability of fundamental physical constants. The project passed the final design review in May 2013 and entered the manufacturing phase. ESPRESSO will be installed at the Paranal Observatory in 2016 and its operation is planned to start by the end of the same year.
Context. High contrast imaging has thoroughly combed through the limited search space accessible with first-generation ground-based adaptive optics instruments and the Hubble Space Telescope. Only a ...few objects were discovered, and many non-detections reported and statistically interpreted. The field is now in need of a technological breakthrough. Aim. Our aim is to open a new search space with first-generation systems such as NACO at the Very Large Telescope, by providing ground-breaking inner working angle (IWA) capabilities in the L' band. The L' band is a sweet spot for high contrast coronagraphy since the planet-to-star brightness ratio is favorable, while the Strehl ratio is naturally higher. Methods. An annular groove phase mask (AGPM) vector vortex coronagraph optimized for the L' band, made from diamond subwavelength gratings was manufactured and qualified in the lab. The AGPM enables high contrast imaging at very small IWA, potentially being the key to unexplored discovery space. Results. Here we present the installation and successful on-sky tests of an L'-band AGPM coronagraph on NACO. Using angular differential imaging, which is well suited to the rotational symmetry of the AGPM, we demonstrated a \Delta L' > 7.5 mag contrast from an IWA ~ 0".09 onwards, during average seeing conditions, and for total integration times of a few hundred seconds.
Prosthetic joint infection by Pasteurella multocida Maradona, J A; Asensi, V; Carton, J A ...
European journal of clinical microbiology & infectious diseases,
08/1997, Volume:
16, Issue:
8
Journal Article
Peer reviewed
Pasteurella multocida is frequently responsible for soft tissue infection in humans, usually following a wound inflicted by a dog or a cat. Involvement of bones or joints is a rare complication, and ...even more infrequent is the infection of a prosthetic joint. We describe a patient with a Pasteurella multocida prosthetic joint infection of the knee and review nine similar cases caused by the same microorganism, reported previously in the literature.
GRAVITY is the second generation Very Large Telescope Interferometer instrument for precision narrow-angle astrometry and interferometric imaging. With its fibre-fed integrated optics, wavefront ...sensors, fringe tracker, beam stabilisation and a novel metrology concept, GRAVITY will push the sensitivity and accuracy of astrometry and interferometric imaging far beyond what is offered today. Providing precision astrometry of order 10 microarcseconds, and imaging with 4-milliarcsecond resolution, GRAVITY will revolutionise dynamical measurements of celestial objects: it will probe physics close to the event horizon of the Galactic Centre black hole; unambiguously detect and measure the masses of black holes in massive star clusters throughout the Milky Way; uncover the details of mass accretion and jets in young stellar objects and active galactic nuclei; and probe the motion of binary stars, exoplanets and young stellar discs. The instrument capabilities of GRAVITY are outlined and the science opportunities that will open up are summarised.
The purpose of this phase II randomised trial was to determine which of two schemes, raltitrexed-irinotecan or raltitrexed-oxaliplatin, offered better activity and less toxicity in patients with ...advanced colorectal cancer (CRC). A total of 94 patients with previously untreated metastatic CRC were included and randomised to receive raltitrexed 3 mg m(-2) followed by oxaliplatin 130 mg m(-2) on day 1 (arm A), or CPT-11 350 mg m(-2) followed by raltitrexed 3 mg m(-2) (arm B). In both arms treatment was repeated every 3 weeks. Intent-to-treat (ITT) analysis showed an overall response rate of 46% (95% CI, 29.5-57.7%) for arm A, and 34% (95% CI, 19.8-48.4%) for arm B. Median time to progression was 8.2 months for arm A and 8.8 months for arm B. After a median follow-up of 14 months, 69% of patients included in arm A were still alive, compared to 59% of those included in arm B. Overall, 31 patients (65%) experienced some episode of toxicity in arm A and 32 patients (70%) in arm B, usually grade 1-2. The most common toxicity was hepatic, with 29 patients (60%) in arm A and 24 patients (62%) in arm B, and was grade 3-4 in four (8%) and four (9%) patients, respectively. In all, 14 patients (29%) from arm A and 24 patients (52%) from arm B had some grade of diarrhoea (P<0.03). Neurologic toxicity was observed in 31 patients (64%) in arm A, and was grade 3-4 in five patients (10%), while a cholinergic syndrome was detected in nine patients (19%) in arm B. There were no differences in haematologic toxicity. One toxic death (2%) occurred in arm A and three (6.5%) in arm B. In conclusion, both schemes have high efficacy as first-line treatment in metastatic CRC and their total toxicity levels are similar. Regimens with raltitrexed seem a reasonable alternative to fluoropyrimidines.
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