33 research outputs found
IBIS 2.0: optical layout and polarimetric unit of the Interferometric BIdimensional Spectrometer 2.0
Nightside condensation of iron in an ultra-hot giant exoplanet
Ultra-hot giant exoplanets receive thousands of times Earth's insolation.
Their high-temperature atmospheres (>2,000 K) are ideal laboratories for
studying extreme planetary climates and chemistry. Daysides are predicted to be
cloud-free, dominated by atomic species and substantially hotter than
nightsides. Atoms are expected to recombine into molecules over the nightside,
resulting in different day-night chemistry. While metallic elements and a large
temperature contrast have been observed, no chemical gradient has been measured
across the surface of such an exoplanet. Different atmospheric chemistry
between the day-to-night ("evening") and night-to-day ("morning") terminators
could, however, be revealed as an asymmetric absorption signature during
transit. Here, we report the detection of an asymmetric atmospheric signature
in the ultra-hot exoplanet WASP-76b. We spectrally and temporally resolve this
signature thanks to the combination of high-dispersion spectroscopy with a
large photon-collecting area. The absorption signal, attributed to neutral
iron, is blueshifted by -11+/-0.7 km s-1 on the trailing limb, which can be
explained by a combination of planetary rotation and wind blowing from the hot
dayside. In contrast, no signal arises from the nightside close to the morning
terminator, showing that atomic iron is not absorbing starlight there. Iron
must thus condense during its journey across the nightside.Comment: Published in Nature (Accepted on 24 January 2020.) 33 pages, 11
figures, 3 table
ESPRESSO at VLT. On-sky performance and first results
Context. ESPRESSO is the new high-resolution spectrograph of ESO's Very Large Telescope (VLT). It was designed for ultra-high radial-velocity (RV) precision and extreme spectral fidelity with the aim of performing exoplanet research and fundamental astrophysical experiments with unprecedented precision and accuracy. It is able to observe with any of the four Unit Telescopes (UTs) of the VLT at a spectral resolving power of 140 000 or 190 000 over the 378.2 to 788.7 nm wavelength range; it can also observe with all four UTs together, turning the VLT into a 16 m diameter equivalent telescope in terms of collecting area while still providing a resolving power of 70 000. Aims: We provide a general description of the ESPRESSO instrument, report on its on-sky performance, and present our Guaranteed Time Observation (GTO) program along with its first results. Methods: ESPRESSO was installed on the Paranal Observatory in fall 2017. Commissioning (on-sky testing) was conducted between December 2017 and September 2018. The instrument saw its official start of operations on October 1, 2018, but improvements to the instrument and recommissioning runs were conducted until July 2019. Results: The measured overall optical throughput of ESPRESSO at 550 nm and a seeing of 0.65âł exceeds the 10% mark under nominal astroclimatic conditions. We demonstrate an RV precision of better than 25 cm s-1 during a single night and 50 cm s-1 over several months. These values being limited by photon noise and stellar jitter shows that the performance is compatible with an instrumental precision of 10 cm s-1. No difference has been measured across the UTs, neither in throughput nor RV precision. Conclusions: The combination of the large collecting telescope area with the efficiency and the exquisite spectral fidelity of ESPRESSO opens a new parameter space in RV measurements, the study of planetary atmospheres, fundamental constants, stellar characterization, and many other fields. Based on GTOs collected at the European Southern Observatory under ESO program(s) 1102.C-0744, 1102.C-0958 and 1104.C-0350 by the ESPRESSO Consortium
Case Report Fusobacterium necrophorum Pharyngitis Complicated by Lemierre's Syndrome
Fusobacterium necrophorum Pharyngitis Complicated by Lemierreâs Syndrome
We report the case of an 18-year-old woman who was referred to our outpatient clinic because of a 2-week history of sore throat, high fever, and neck tenderness unresponsive to a 7-day amoxicillin/clavulanic acid course. Infectious mononucleosis was initially suspected, but an extremely high value of procalcitonin and clinical deterioration suggested a bacterial sepsis, prompting the patient admission to our internal medicine ward. Blood cultures were positive for Fusobacterium necrophorum. CT scan detected a parapharyngeal abscess, a right internal jugular vein thrombosis, and multiple bilateral lung abscesses, suggesting the diagnosis of Lemierreâs syndrome. The patient was treated with a 2-week course of metronidazole and meropenem with a gradual clinical recovery. She was thereafter discharged home with metronidazole and amoxicillin/clavulanic acid for 14 days and a 3-month course of enoxaparin, experiencing an uneventful recovery. The present case highlights the importance of taking into consideration the Lemierreâs syndrome whenever a pharyngotonsillitis has a severe and unusual course
Handling quality in crowdsourced geographic information
While spatial information quality is an established discipline in traditional scientific geographical information (GI), standards and protocols for representing and assessing the quality of geographic contributions generated by volunteers or by the generic âweb crowdâ are still missing. This work offers an analysis of strategies for quality control and describes a simple representation of the components of the quality in crowdsourced GI. In this framework, and based on the research carried out in Criscuolo et al. (2014), we also introduce a methodology for quality assessment, based on the given representation, which goes beyond the limitations of previous methods in the literature defined for a specific purpose, being able to deal with many quality features, GI categories, and types of application. The method is designed as a decision making approach, so flexible as to take into account the purpose of GI analysis, and so transparent as to make explicit the criteria driving to quality evaluation, namely the quality features (e.g. the credibility of the volunteers, or the accuracy of the spatial features, etc.) and their relevance
Valutazione di due metodi commerciali per la diagnosi rapida di Mycobacterium tuberculosis complex in campioni clinici
Multimodal Comparison of Diabetic Neuropathy in Aged Streptozotocin-Treated SpragueâDawley and Zucker Diabetic Fatty Rats
The development and progression of diabetic polyneuropathy (DPN) are due to multiple mechanisms. The creation of reliable animal models of DPN has been challenging and this issue has not yet been solved. However, despite some recognized differences from humans, most of the current knowledge on the pathogenesis of DPN relies on results achieved using rodent animal models. The simplest experimental DPN model reproduces type 1 diabetes, induced by massive chemical destruction of pancreatic beta cells with streptozotocin (STZ). Spontaneous/transgenic models of diabetes are less frequently used, mostly because they are less predictable in clinical course, more expensive, and require a variable time to achieve homogeneous metabolic conditions. Among them, Zucker diabetic fatty (ZDF) rats represent a typical type 2 diabetes model. Both STZ-induced and ZDF rats have been extensively used, but only very few studies have compared the long-term similarities and differences existing between these two models. Moreover, inconsistencies have been reported regarding several aspects of short-term in vivo studies using these models. In this study, we compared the long-term course of DPN in STZ-treated SpragueâDawley and ZDF rats with a multimodal set of readout measures
STUDIO MOLECOLARE DELLE FARMACORESISTENZE DI Mycobacterium tuberculosis IN CAMPIONI RESPIRATORI
The length of SNCA Rep1 microsatellite may influence cognitive evolution in Parkinson's disease
Background: Alpha-synuclein is a constituent of Lewy bodies and mutations of its gene cause familial Parkinson's disease (PD). A previous study showed that a variant of the alpha-synuclein gene (SNCA), namely the 263 bp allele of Rep1 was associated with faster motor progression in PD. On the contrary, a recent report failed to detect a detrimental effect of Rep1 263 on both motor and cognitive outcomes in PD. Aim of this study was to evaluate the influence of the Rep1 variants on disease progression in PD patients. Methods: We recruited and genotyped for SNCA Rep1 426 PD patients with age at onset 6540 years and disease duration 654 years. We then analyzed frequency and time of occurrence of wearing-off, dyskinesia, freezing of gait, visual hallucinations, and dementia using a multivariate Cox's proportional hazards regression model. Results: SNCA Rep1 263 carriers showed significantly increased risk of both dementia (HR = 3.03) and visual hallucinations (HR = 2.69) compared to 263 non-carriers. Risk of motor complications did not differ in the two groups. Conclusion: SNCA Rep1 263 allele is associated with a worse cognitive outcome in PD