Context. Transition disks offer the extraordinary opportunity to look for newly born planets and to investigate the early stages of planet formation. Aim. In this context we observed the Herbig A5 ...star MWC 758 with the L′-band vector vortex coronagraph installed in the near-infrared camera and spectrograph NIRC2 at the Keck II telescope, with the aim of unveiling the nature of the spiral structure by constraining the presence of planetary companions in the system. Methods. Our high-contrast imaging observations show a bright (ΔL′ = 7.0 ± 0.3 mag) point-like emission south of MWC 758 at a deprojected separation of ~20 au (r = 0.′′111 ± 0.′′004) from the central star. We also recover the two spiral arms (southeast and northwest), already imaged by previous studies in polarized light, and discover a third arm to the southwest of the star. No additional companions were detected in the system down to 5 Jupiter masses beyond 0.′′6 from the star. Results. We propose that the bright L′-band emission could be caused by the presence of an embedded and accreting protoplanet, although the possibility of it being an asymmetric disk feature cannot be excluded. The spiral structure is probably not related to the protoplanet candidate, unless on an inclined and eccentric orbit, and it could be due to one (or more) yet undetected planetary companions at the edge of or outside the spiral pattern. Future observations and additional simulations will be needed to shed light on the true nature of the point-like source and its link with the spiral arms.
Context. The annular groove phase mask (AGPM) is one possible implementation of the vector vortex coronagraph, where the helical phase ramp is produced by a concentric subwavelength grating. For ...several years, we have been manufacturing AGPMs by etching gratings into synthetic diamond substrates using inductively coupled plasma etching. Aims. We aim to design, fabricate, optimize, and evaluate new L-band AGPMs that reach the highest possible coronagraphic performance, for applications in current and forthcoming infrared high-contrast imagers. Methods. Rigorous coupled wave analysis (RCWA) is used for designing the subwavelength grating of the phase mask. Coronagraphic performance evaluation is performed on a dedicated optical test bench. The experimental results of the performance evaluation are then used to accurately determine the actual profile of the fabricated gratings, based on RCWA modeling. Results. The AGPM coronagraphic performance is very sensitive to small errors in etch depth and grating profile. Most of the fabricated components therefore show moderate performance in terms of starlight rejection (a few 100:1 in the best cases). Here we present new processes for re-etching the fabricated components in order to optimize the parameters of the grating and hence significantly increase their coronagraphic performance. Starlight rejection up to 1000:1 is demonstrated in a broadband L filter on the coronagraphic test bench, which corresponds to a raw contrast of about 10-5 at two resolution elements from the star for a perfect input wave front on a circular, unobstructed aperture. Conclusions. Thanks to their exquisite performance, our latest L-band AGPMs are good candidates for installation in state of the art and future high-contrast thermal infrared imagers, such as METIS for the E-ELT.
ABSTRACT An optical vortex coronagraph has been implemented within the NIRC2 camera on the Keck II telescope and used to carry out on-sky tests and observations. The development of this new L′-band ...observational mode is described, and an initial demonstration of the new capability is presented: a resolved image of the low-mass companion to HIP 79124, which had previously been detected by means of interferometry. With HIP 79124 B at a projected separation of 186.5 mas, both the small inner working angle of the vortex coronagraph and the related imaging improvements were crucial in imaging this close companion directly. Due to higher Strehl ratios and more relaxed contrasts in L′ band versus H band, this new coronagraphic capability will enable high-contrast, small-angle observations of nearby young exoplanets and disks on a par with those of shorter-wavelength extreme adaptive optics coronagraphs.
French Guiana, a tropical country, is characterised by a young and multi-ethnic population. Difficulties in accessing safe water sources lead to outbreaks of gastroenteritis. The objectives of this ...study were (1) to describe the microbiological profile of shigella strains isolated in western French Guiana, including antimicrobial susceptibility and the distribution of strains in terms of species and serotypes and (2) to estimate the incidence of shigellosis in children under 5 years old. A retrospective observational study was conducted of 213 cases of shigellosis diagnosed in the biology department of the hospital centre for western French Guiana between 2000 and 2012 in children under 5 years old. The serogroups (formerly known as species) that predominates in French Guiana was Shigella flexneri. No resistance was observed to fluoroquinolones or to third-generation cephalosporins. The average incidence of shigellosis in children under 5 years old in western French Guiana was estimated at 189.6 cases per 100 000 inhabitants per year. Shigellosis is a public health problem in western French Guiana. These infections suggest the difficulties in accessing safe water sources and the lack of public sanitation. A quadrivalent vaccine containing Shigella sonnei and three serotypes of S. flexneri (S. flexneri 2a, 3a and 6) could provide broad coverage against shigella infections.
This research investigated how the carbon isotopic composition of food source (δ13Cfood) and dissolved inorganic carbon (δ13CDIC) influences the carbon isotopic composition of Pecten maximus shells ...(δ13Cshell) under both experimental and natural conditions. The objectives are to better understand the relationship between P. maximus and its environment, and to specifically distinguish conditions under which calcification is influenced by respired CO2 derived from food sources versus conditions in which calcification uses inorganic carbon from seawater. Laboratory experiment investigated carbon incorporation into shell carbonates by maintaining scallops under conditions where the stable carbon isotopic composition of food sources was considerably depleted (−54‰), relative to values observed in the natural environment (−21‰). Laboratory experiment ran for 78days under three temperature conditions, 15°C, 21°C and 25°C. A survey of the environmental parameters and stable carbon isotopic composition into shell carbonate of natural population of P. maximus was also realized during the same year in the Bay of Brest, France. Data collected from both laboratory experiment and the natural environment confirmed that both δ13CDIC and δ13Cfood influence δ13Cshell values and that organic carbon incorporation (CM) averages about 10% (4.3–6.8% under experimental conditions and 1.9–16.6% in the natural environment). The shift in stable carbon isotopic composition from the uptake of depleted food sources under experimental conditions realized a marked divergence in the predicted equilibrium between calcium carbonate and ambient bicarbonate, relative to the natural environment. This offset was 1.7±0.6‰ for scallops in their natural environment and 2.5±0.5 and 3.2±0.9‰ for scallops under experimental conditions at water temperatures of 15°C and 21°C, respectively. The offset of 3‰ for scallops subjected to laboratory experiment could not be explained in light of growth rate but may be related to food supply and/or temperature. Food source and temperature effects may also explain the annual variation observed in CM values measured from scallops in their natural environment. CM estimation from the natural population of P. maximus varied seasonally from around 2% at the end of winter, to 12% in summer. The seasonal variation resembles variability in the carbon isotopic composition of the food sources throughout the year with an exception at the end of winter.
Objective
To evaluate the performance of the
Gout-calculator
in a cohort of consecutive acute arthritis affecting large and intermediate joints (without an attack on hallux or midfoot joints).
...Methods
A retrospective study.
Gout-calculator
data were collected in medical records of patients included in the prospective consecutive cohort of acute arthritis called SYNOLACTATE. The diagnosis of gout was defined by the presence of sodium urate crystals in synovial fluid. The diagnostic performance of the
Gout-calculator
was studied by performing an ROC curve with the calculation of its AUC (95% CI) as well as the calculation of Sensitivity (Se), Specificity (Sp), and positive likelihood ratio (LR+).
Results
170 patients with acute arthritis were included. Variables associated with the diagnosis of gout were as follows: serum uric acid > 350 μmol/L (OR 5.52 (2.52–12.1),
p
< 0.001), joint redness (OR 5.08 (1.85–14.0),
p
= 0.001), previous patient-reported arthritis attack (OR 4.04 (1.92–8.49),
p
< 0.001), male (OR 3.00 (1.17–7.69),
p
= 0.02), hypertension or cardiovascular disease (OR 2.33 (1.07–5.06),
p
= 0.03). The median (IQR) of
Gout-calculator
was significantly higher in gouty arthritis (7.0 5.5–8.1) than in associated-CPP acute arthritis (4.0 2.0–5.8), septic arthritis (3.0 2.0–5.1), or others arthritis (3.5 2.0–5.5). The AUC was 0.833 (0.768–0.897) with for the threshold ≥ 8, a Se at 27.5% (0.161–0.428), Sp 97.7% (0.934–0.992), and LR+ 11.9 (3.5-40).
Conclusion
Despite diagnostic performances close to those published, the use of the
Gout-calculator
is not sufficient for the diagnosis of gout or to exclude the differential diagnosis of septic arthritis in the SYNOLACTATE cohort.
Key Points:
• For a Gout-calculator threshold of ≤ 4, Sensitivity is 92.5%, Specificity 50.8% and LR− 0.15 to the gout diagnosis.
• For a Gout-calculator threshold of > = 8, Sensitivity is 27.5%, Specificity 97.7% and LR+ 11.9 to the gout diagnosis.
• In a population of acute arthritis affecting large joints, Gout-calculator is not sufficient to discriminate between gouty arthritis and septic arthritis.
Although many studies have investigated the benthic environment of temperate marine waters, little is known about the acoustic behaviour of the organisms in these habitats, particularly crustaceans. ...This study focused on the acoustic behaviour of large crustaceans in NE Atlantic coastal regions. A total of 11 crustacean species were recorded in tank-based experiments to identify sound-producing species and the behaviours associated with their sounds as well as to quantitatively characterise and compare the sounds. A total of 34 sounds were associated with behaviours such as moving, feeding, mandible rubbing, swimming, species-specific behaviour and other unidentified behaviours. The sounds included single pulse and pulse train signals that were distributed across a peak frequency spectrum of 3 to 45 kHz with received levels between 93 and 142 dB re 1 mu Pa (peak to peak). The results demonstrated that Brachyura had the most diverse sound types. Using a combination of several acoustic features, 24% of the recorded sounds appeared to have a high potential to be differentiated in field recordings: the feeding sound of Cancer pagurus, Carcinus maenas, Necora puber and Pachygrapsus marmoratus; the species-specific sound of C. pagurus and Galathea squamifera; and the pulse train sound associated with unidentified behaviours of Lophozozymus incisus and N. puber. These findings extend the existing crustacean acoustic library in marine ecosystems and contribute to our understanding of in situ acoustic recordings in temperate regions.
Summary
Disseminated histoplasmosis (DH) is the most current revelation mode of AIDS in French Guiana. We describe the clinical and paraclinical presentation of DH, diagnostic tools, evolution and ...factors associated with 1‐year mortality in HIV‐infected patients from western French Guiana. Microbiologically proven AIDS‐related DH in Saint Laurent du Maroni's hospital between May 2002 and May 2012 were retrospectively included. Among the 82 patients included, 58 (71%) were male, 44 (53%) presented concurrent histoplasmosis and HIV diagnosis and 63 (80%) had a CD4 cell count under 50 cells μL−1. Almost all patients had weight loss (97%) and fever (95%), while 84% had digestive symptoms (63% diarrhoea), 55% lymphadenopathy, and 49% respiratory symptoms. Documented and presumed locations of H. capsulatum var capsulatum (Hcc) concerned almost all organs, with a particular affinity for the bone marrow and the digestive system. Co‐infections were associated in 65%. Following treatment initiation, 10 patients (13%) died within 1 month and 17 patients (25%) died within a year. DH is a polymorphous systemic mycosis with haematological and digestive tropism. Co‐infections are frequent and mortality rate is high.
Food sources of the European abalone
Haliotis tuberculata
throughout its life cycle are still to be clarified in nature. A novel non-destructive method of digital shell color analysis to reveal the ...diets of European abalone (ormer) was developed in this study. The method was calibrated using ormers reared under experimental conditions in North Western Brittany in 2012 and fed a controlled monospecific diet to define the shell hues associated with various macroalgae (i.e., Rhodophyta, Chlorophyta, and Phaeophyta). General food preferences were established by comparing the shell hue of wild adult ormers and experimental adult ormers. Shell hue corresponds to the color tint in the HSL color space measured on digital pictures of the shell. Experimentally, shell hue values differed according to treatment, with the most yellow-green hue (72°) for ormers fed
Saccharina
sp. and the coral hue (25°) for ormers fed
Palmaria palmata
. High variation in shell color of wild ormers was observed according to the sampling site and/or ontogeny. The diet of wild ormers may be related to the abundance of different drifting algae in their respective habitats. Thus, this non-destructive and easy-to-use technique appears to be a promising tool for determining the diet of
Haliotis
species and, perhaps, other herbivorous mollusks.
PDF
