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Publicações

Publicações por CTM

2020

Identifying baseline clinical features of people with COVID-19

Autores
Ferreira-Santos, D; Maranhao, P; Monteiro-Soares, M;

Publicação

Abstract
Objectives: To describe baseline clinical characteristics of adult patients with COVID-19. Methods: We conducted a scoping review of the evidence available at LitCovid, until March 23th, 2020, and selected articles that reported the prevalence of socio-demographic characteristics, symptoms and co-morbidities in adults with COVID-19. Results: In total, 1 572 publications were published on LitCovid. We have included 56 articles in our analysis, with 89% conducted in China, and 75% contained inpatients. Three studies were conducted in North America and one in Europe. Participants age ranged from 28 to 70 years, with balanced gender distribution. Proportion of asymptomatic cases were from 2 to 79%. The most common reported symptoms were fever [4-99%], cough [4-92%], dyspnoea/shortness of breath [1-90%], fatigue 4-89%], myalgia [3-65%], and pharyngalgia [2-61%], while regarding co-morbidities we found cardiovascular disease [1-40%], hypertension [0-40%] and cerebrovascular disease [1-40%]. Such heterogeneity impairs the conduction of meta-analysis. Conclusions: The infection by COVID-19 seems to affect people in a very diverse manner and with different characteristics. With the available data it is not possible to clearly identify those at higher risk of being infected with this condition. Furthermore, the evidence from countries other than China is, at the day, too scarce.

2020

Identifying common baseline clinical features of COVID-19: a scoping review

Autores
Ferreira Santos, D; Maranhao, P; Monteiro Soares, M;

Publicação
BMJ OPEN

Abstract
Objectives Our research question was: what are the most frequent baseline clinical characteristics in adult patients with COVID-19? Our major aim was to identify common baseline clinical features that could help recognise adult patients at high risk of having COVID-19. Design We conducted a scoping review of all the evidence available at LitCovid, until 23 March 2020. Setting Studies conducted in any setting and any country were included. Participants Studies had to report the prevalence of sociodemographic characteristics, symptoms and comorbidities specifically in adults with a diagnosis of infection by SARS-CoV-2. Results In total, 1572 publications were published on LitCovid. We have included 56 articles in our analysis, with 89% conducted in China and 75% containing inpatients. Three studies were conducted in North America and one in Europe. Participants' age ranged from 28 to 70 years, with balanced gender distribution. The proportion of asymptomatic cases were from 2% to 79%. The most common reported symptoms were fever (4%-99%), cough (4%-92%), dyspnoea/shortness of breath (1%-90%), fatigue (4%-89%), myalgia (3%-65%) and pharyngalgia (2%-61%), while regarding comorbidities, we found cardiovascular disease (1%-40%), hypertension (0%-40%) and cerebrovascular disease (1%-40%). Such heterogeneity impaired the conduction of meta-analysis. Conclusions The infection by COVID-19 seems to affect people in a very diverse manner and with different characteristics. With the available data, it is not possible to clearly identify those at higher risk of being infected with this condition. Furthermore, the evidence from countries other than China is, at the moment, too scarce.

2020

A measure of the size of the magnetospheric accretion region in TW Hydrae

Autores
Lopez, RG; Natta, A; Garatti, ACO; Ray, TP; Fedriani, R; Koutoulaki, M; Klarmann, L; Perraut, K; Sanchez Bermudez, J; Benisty, M; Dougados, C; Labadie, L; Brandner, W; Garcia, PJV; Henning, T; Caselli, P; Duvert, G; de Zeeuw, T; Grellmann, R; Abuter, R; Amorim, A; Baub?ck, M; Berger, JP; Bonnet, H; Buron, A; Cl?net, Y; du Foresto, VC; de Wit, W; Eckart, A; Eisenhauer, F; Filho, M; Gao, F; Dabo, CEG; Gendron, E; Genzel, R; Gillessen, S; Habibi, M; Haubois, X; Haussmann, F; Hippler, S; Hubert, Z; Horrobin, M; Rosales, AJ; Jocou, L; Kervella, P; Kolb, J; Lacour, S; Le Bouquin, JB; L?na, P; Ott, T; Paumard, T; Perrin, G; Pfuhl, O; Ramirez, A; Rau, C; Rousset, G; Scheithauer, S; Shangguan, J; Stadler, J; Straub, O; Straubmeier, C; Sturm, E; van Dishoeck, E; Vincent, F; von Fellenberg, S; Widmann, F; Wieprecht, E; Wiest, M; Wiezorrek, E; Woillez, J; Yazici, S; Zins, G;

Publicação
NATURE

Abstract
Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magnetic field. This is thought to be strong enough to truncate the disk close to the corotation radius, at which the disk rotates at the same rate as the star. Spectro-interferometric studies in young stellar objects show that hydrogen emission (a well known tracer of accretion activity) mostly comes from a region a few milliarcseconds across, usually located within the dust sublimation radius(1-3). The origin of the hydrogen emission could be the stellar magnetosphere, a rotating wind or a disk. In the case of intermediate-mass Herbig AeBe stars, the fact that Brackett gamma (Br gamma) emission is spatially resolved rules out the possibility that most of the emission comes from the magnetosphere(4-6)because the weak magnetic fields (some tenths of a gauss) detected in these sources(7,8)result in very compact magnetospheres. In the case of T Tauri sources, their larger magnetospheres should make them easier to resolve. The small angular size of the magnetosphere (a few tenths of a milliarcsecond), however, along with the presence of winds(9,10)make the interpretation of the observations challenging. Here we report optical long-baseline interferometric observations that spatially resolve the inner disk of the T Tauri star TW Hydrae. We find that the near-infrared hydrogen emission comes from a region approximately 3.5 stellar radii across. This region is within the continuum dusty disk emitting region (7 stellar radii across) and also within the corotation radius, which is twice as big. This indicates that the hydrogen emission originates in the accretion columns (funnel flows of matter accreting onto the star), as expected in magnetospheric accretion models, rather than in a wind emitted at much larger distance (more than one astronomical unit). The size of the inner disk of the T Tauri star TW Hydrae is determined using optical long-baseline interferometric observations, indicating that hydrogen emission comes from a region approximately 3.5 stellar radii across.

2020

Modeling the orbital motion of Sgr A*'s near-infrared flares

Autores
Baubock, M; Dexter, J; Abuter, R; Amorim, A; Berger, JP; Bonnet, H; Brandner, W; Clenet, Y; du Foresto, VC; de Zeeuw, PT; Duvert, G; Eckart, A; Eisenhauer, F; Schreiber, NMF; Gao, F; Garcia, P; Gendron, E; Genzel, R; Gerhard, O; Gillessen, S; Habibi, M; Haubois, X; Henning, T; Hippler, S; Horrobin, M; Jimenez Rosales, A; Jocou, L; Kervella, P; Lacour, S; Lapeyrere, V; Le Bouquin, JB; Lena, P; Ott, T; Paumard, T; Perraut, K; Perrin, G; Pfuhl, O; Rabien, S; Coira, GR; Rousset, G; Scheithauer, S; Stadler, J; Sternberg, A; Straub, O; Straubmeier, C; Sturm, E; Tacconi, LJ; Vincent, F; von Fellenberg, S; Waisberg, I; Widmann, F; Wieprecht, E; Wiezorrek, E; Woillez, J; Yazici, S;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Infrared observations of Sgr A* probe the region close to the event horizon of the black hole at the Galactic center. These observations can constrain the properties of low-luminosity accretion as well as that of the black hole itself. The GRAVITY instrument at the ESO VLTI has recently detected continuous circular relativistic motion during infrared flares which has been interpreted as orbital motion near the event horizon. Here we analyze the astrometric data from these flares, taking into account the effects of out-of-plane motion and orbital shear of material near the event horizon of the black hole. We have developed a new code to predict astrometric motion and flux variability from compact emission regions following particle orbits. Our code combines semi-analytic calculations of timelike geodesics that allow for out-of-plane or elliptical motions with ray tracing of photon trajectories to compute time-dependent images and light curves. We apply our code to the three flares observed with GRAVITY in 2018. We show that all flares are consistent with a hotspot orbiting at R similar to 9 gravitational radii with an inclination of i similar to 140 degrees. The emitting region must be compact and less than similar to 5 gravitational radii in diameter. We place a further limit on the out-of-plane motion during the flare.

2020

The GRAVITY young stellar object survey: II. First spatially resolved observations of the CO bandhead emission in a high-mass YSO

Autores
Caratti o Garatti, A; Fedriani, R; Garcia Lopez, R; Koutoulaki, M; Perraut, K; Linz, H; Brandner, W; Garcia, P; Klarmann, L; Henning, T; Labadie, L; Sanchez-Bermudez, J; Lazareff, B; van Dishoeck, EF; Caselli, P; de Zeeuw, PT; Bik, A; Benisty, M; Dougados, C; Ray, TP; Amorim, A; Berger, J; Clénet, Y; Coudé du Foresto, V; Duvert, G; Eckart, A; Eisenhauer, F; Gao, F; Gendron, E; Genzel, R; Gillessen, S; Gordo, P; Jocou, L; Horrobin, M; Kervella, P; Lacour, S; Le Bouquin, J; Léna, P; Grellmann, R; Ott, T; Paumard, T; Perrin, G; Rousset, G; Scheithauer, S; Shangguan, J; Stadler, J; Straub, O; Straubmeier, C; Sturm, E; Thi, WF; Vincent, FH; Widmann, F;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Context. The inner regions of the discs of high-mass young stellar objects (HMYSOs) are still poorly known due to the small angular scales and the high visual extinction involved.Aims. We deploy near-infrared spectro-interferometry to probe the inner gaseous disc in HMYSOs and investigate the origin and physical characteristics of the CO bandhead emission (2.3-2.4 mu m).Methods. We present the first GRAVITY/VLTI observations at high spectral (R=4000) and spatial (mas) resolution of the CO overtone transitions in NGC 2024 IRS 2.Results. The continuum emission is resolved in all baselines and is slightly asymmetric, displaying small closure phases (<= 8 degrees). Our best ellipsoid model provides a disc inclination of 34 degrees +/- 1 degrees, a disc major axis position angle (PA) of 166 degrees +/- 1 degrees, and a disc diameter of 3.99 +/- 0.09 mas (or 1.69 +/- 0.04 au, at a distance of 423 pc). The small closure phase signals in the continuum are modelled with a skewed rim, originating from a pure inclination effect. For the first time, our observations spatially and spectrally resolve the first four CO bandheads. Changes in visibility, as well as differential and closure phases across the bandheads are detected. Both the size and geometry of the CO-emitting region are determined by fitting a bidimensional Gaussian to the continuum-compensated CO bandhead visibilities. The CO-emitting region has a diameter of 2.74 +/-(0.08)(0.07) +/- 0.07 0.08 mas (1.16 +/- 0.03 au), and is located in the inner gaseous disc, well within the dusty rim, with inclination and PA matching the dusty disc geometry, which indicates that both dusty and gaseous discs are coplanar. Physical and dynamical gas conditions are inferred by modelling the CO spectrum. Finally, we derive a direct measurement of the stellar mass of M-* similar to 14.7(-3.6)(+2)M(circle dot) M * similar to 14 . 7 - 3.6 + 2 M circle dot by combining our interferometric and spectral modelling results.

2020

A mass optimized support and access structure for ESO's Mid-infrared E-ELT Imager and Spectrograph (METIS)

Autores
Boné, A; Amorim, A; Rodrigues, H; Lesman, D; Filho, M; Garcia, P;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
Extremely Large Telescopes are considered worldwide as one of the highest priorities in ground-based astronomy, for they have the potential to vastly advance astrophysical knowledge with detailed studies of subjects including the first objects in the Universe, exoplanets, super-massive black holes, and the nature and distribution of the dark matter and dark energy which dominate the Universe. ESO is building its own Extremely Large optical/infrared Telescope, the ELT. This new telescope will have a 39 m main mirror and will be the largest optical/NIR telescope in the world, able to work at the diffraction limit. METIS, one of the first light instruments of the ELT, has powerful imaging and spectrographic capabilities on the thermal wavelengths. It will allow the investigation of key properties of a wide range of objects, from exoplanets to star forming regions, and it is highly complementary to other facilities such as the JWST. METIS is an extremely complex instrument, weighing almost 11 ton, and requiring high positioning and steering precisions. Here we present the ELT's METIS' Warm Support Structure. It consists on a 7 leg elevation platform, a passive hexapod capable of providing METIS with sub-millimetre and arcsecond positioning and steering resolutions, and an access platform where personnel can perform in-situ maintenance activities. The support structure weighs less than 5 ton and is capable of surviving earthquake conditions with accelerations up to 5g. The current design is supported by FEM simulations in ANSYS®, and was approved for Phase C. © 2020 SPIE

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