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Publicações

Publicações por CTM

2017

Implementing Guidelines for Causality Assessment of Adverse Drug Reaction Reports: A Bayesian Network Approach

Autores
Rodrigues, PP; Santos, DF; Silva, A; Polónia, J; Vaz, IR;

Publicação
Artificial Intelligence in Medicine - 16th Conference on Artificial Intelligence in Medicine, AIME 2017, Vienna, Austria, June 21-24, 2017, Proceedings

Abstract
In pharmacovigilance, reported cases are considered suspected adverse drug reactions (ADR). Health authorities have thus adopted structured causality assessment methods, allowing the evaluation of the likelihood that a medicine was the causal agent of an adverse reaction. The aim of this work was to develop and validate a new causality assessment support system used in a regional pharmacovigilance centre. A Bayesian network was developed, for which the structure was defined by an expert, aiming at implementing the current guidelines for causality assessment, while the parameters were learnt from 593 completely-filled ADR reports evaluated by the Portuguese Northern Pharmacovigilance Centre expert between 2000 and 2012. Precision, recall and time to causality assessment (TTA) was evaluated, according to the WHO causality assessment guidelines, in a retrospective cohort of 466 reports (April to September 2014) and a prospective cohort of 1041 reports (January to December 2015). Results show that the network was able to easily identify the higher levels of causality (recall above 80%), although strugling to assess reports with a lower level of causality. Nonetheless, the median (Q1:Q3) TTA was 4 (2:8) days using the network and 8 (5:14) days using global introspection, meaning the network allowed a faster time to assessment, which has a procedural deadline of 30 days, improving daily activities in the centre.

2017

The 2008 outburst in the young stellar system Z CMa III. Multi-epoch high-angular resolution images and spectra of the components in near-infrared

Autores
Bonnefoy, M; Chauvin, G; Dougados, C; Kospal, A; Benisty, M; Duchene, G; Bouvier, J; Garcia, PJV; Whelan, E; Antoniucci, S; Podio, L;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Context. Z CMa is a complex pre-main sequence binary with a current separation of 110 mas, known to consist of an FU Orionis star (SE component) and an embedded Herbig Be star (NW component). Although it represents a well-studied and characterized system, the origin of photometric variabilities, the component properties, and the physical configuration of the system remain mostly unknown. Aims. Immediately when the late-2008 outburst of Z CMa was announced to the community, we initiated a high angular resolution imaging campaign aimed at characterizing the outburst state of both components of the system in the near-infrared. Methods. We used the VLT/NACO and the Keck/NIRC2 near-infrared adaptive optics instrument to monitor the astrometric position and the near-infrared photometry of the Z CMa components during the outburst phase and one year after. The VLT/SINFONI and Keck/OSIRIS integral field spectroscrographs were in addition used to characterize for the first time the resolved spectral properties of the FU Orionis and the Herbig Be component during and after the outburst. Results. We confirm that the NW star dominates the system flux in the 1.1-3.8 mu m range and is responsible for the photometric outburst. We extract the first medium-resolution (R similar to 2000-4000) near-infrared (1.1-2.4 mu m) spectra of the individual components. The SE component has a spectrum typical of FU Orionis objects. The NW component spectrum is characteristic of embedded outbursting protostars and EX Or objects. It displays numerous emission lines whose intensity correlates with the system activity. In particular, we find a correlation between the Br gamma equivalent width and the system brightness. The bluing of the continuum of the NW component along with the absolute flux and color-variation of the system during the outburst suggests that the outburst was caused by a complex interplay between a variation of the extinction in the line of sight of the NW component on one hand, and the emission of shocked regions close to the NW component on the other. We confirm the recently reported wiggling of the SE component jet from [Fe II] line emission. We find a point-like structure associated with a peak emission at 2.098 mu m coincidental with the clump or arm seen in broadband polarization di ff erential imaging as well as additional di ff use emission along a PA = 214 degrees. The origin of these two structures is unclear and deserves further investigation.

2017

First light for GRAVITY: Phase referencing optical interferometry for the Very Large Telescope Interferometer

Autores
Abuter, R; Accardo, M; Amorim, A; Anugu, N; Avila, G; Azouaoui, N; Benisty, M; Berger, JP; Blind, N; Bonnet, H; Bourget, P; Brandner, W; Brast, R; Buron, A; Burtscher, L; Cassaing, F; Chapron, F; Choquet, E; Clenet, Y; Collin, C; du Foresto, VC; de Wit, W; de Zeeuw, PT; Deen, C; Delplancke Stroebele, F; Dembet, R; Derie, F; Dexter, J; Duvert, G; Ebert, M; Eckart, A; Eisenhauer, F; Esselborn, M; Fedou, P; Finger, G; Garcia, P; Dabo, CEG; Lopez, RG; Gendron, E; Genzel, R; Gillessen, S; Gonte, F; Gordo, P; Grould, M; Groezinger, U; Guieu, S; Haguenauer, P; Hans, O; Haubois, X; Haug, M; Haussmann, F; Henning, T; Hippler, S; Horrobin, M; Huber, A; Hubert, Z; Hubin, N; Hummel, CA; Jakob, G; Janssen, A; Jochum, L; Jocou, L; Kaufer, A; Kellner, S; Kendrew, S; Kern, L; Kervella, P; Kiekebusch, M; Klein, R; Kok, Y; Kolb, J; Kulas, M; Lacour, S; Lapeyrere, V; Lazareff, B; Le Bouquin, JB; Lena, P; Lenzen, R; Leveque, S; Lippa, M; Magnard, Y; Mehrgan, L; Mellein, M; Merand, A; Moreno Ventas, J; Moulin, T; Mueller, E; Mueller, F; Neumann, U; Oberti, S; Ott, T; Pallanca, L; Panduro, J; Pasquini, L; Paumard, T; Percheron, I; Perraut, K; Perrin, G; Pflueger, A; Pfuhl, O; Duc, TP; Plewa, PM; Popovic, D; Rabien, S; Ramirez, A; Ramos, J; Rau, C; Riquelme, M; Rohloff, RR; Rousset, G; Sanchez Bermudez, J; Scheithauer, S; Schoeller, M; Schuhler, N; Spyromilio, J; Straubmeier, C; Sturm, E; Suarez, M; Tristram, KRW; Ventura, N; Vincent, F; Waisberg, I; Wank, I; Weber, J; Wieprecht, E; Wiest, M; Wiezorrek, E; Wittkowski, M; Woillez, J; Wolff, B; Yazici, S; Ziegler, D; Zins, G;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
GRAVITY is a new instrument to coherently combine the light of the European Southern Observatory Very Large Telescope Interferometer to form a telescope with an equivalent 130m diameter angular resolution and a collecting area of 200 m(2). The instrument comprises fiber fed integrated optics beam combination, high resolution spectroscopy, built-in beam analysis and control, near-infrared wavefront sensing, phase-tracking, dual-beam operation, and laser metrology. GRAVITY opens up to optical/infrared interferometry the techniques of phase referenced imaging and narrow angle astrometry, in many aspects following the concepts of radio interferometry. This article gives an overview of GRAVITY and reports on the performance and the first astronomical observations during commissioning in 2015/16. We demonstrate phase-tracking on stars as faint as m(K) approximate to 10 mag, phase-referenced interferometry of objects fainter than m(K) approximate to 15 mag with a limiting magnitude of m(K) approximate to 17 mag, minute long coherent integrations, a visibility accuracy of better than 0.25%, and spectro-differential phase and closure phase accuracy better than 0.5 degrees, corresponding to a differential astrometric precision of better than ten microarcseconds (as). The dual-beam astrometry, measuring the phase difference of two objects with laser metrology, is still under commissioning. First observations show residuals as low as 50 mu as when following objects over several months. We illustrate the instrument performance with the observations of archetypical objects for the different instrument modes. Examples include the Galactic center supermassive black hole and its fast orbiting star S2 for phase referenced dual-beam observations and infrared wavefront sensing, the high mass X-ray binary BP Cru and the active galactic nucleus of PDS 456 for a few mu as spectro-differential astrometry, the T Tauri star S CrA for a spectro-differential visibility analysis, xi Tel and 24 Cap for high accuracy visibility observations, and eta Car for interferometric imaging with GRAVITY.

2017

Accretion-ejection morphology of the microquasar SS 433 resolved at sub-au scale

Autores
Petrucci, PO; Waisberg, I; Le Bouquin, JB; Dexter, J; Dubus, G; Perraut, K; Kervella, P; Abuter, R; Amorim, A; Anugu, N; Berger, JP; Blind, N; Bonnet, H; Brandner, W; Buron, A; Choquet, E; Clenet, Y; de Wit, W; Deen, C; Eckart, A; Eisenhauer, F; Finger, G; Garcia, P; Lopez, RG; Gendron, E; Genzel, R; Gillessen, S; Gonte, F; Haubois, X; Haug, M; Haussmann, F; Henning, T; Hippler, S; Horrobin, M; Hubert, Z; Jochum, L; Jocou, L; Kok, Y; Kolb, J; Kulas, M; Lacour, S; Lazareff, B; Lena, P; Lippa, M; Merand, A; Mueller, E; Ott, T; Panduro, J; Paumard, T; Perrin, G; Pfuhl, O; Ramos, J; Rau, C; Rohlo, RR; Rousset, G; Sanchez Bermudez, J; Scheithauer, S; Schoeller, M; Straubmeier, C; Sturm, E; Vincent, F; Wank, I; Wieprecht, E; Wiest, M; Wiezorrek, E; Wittkowski, M; Woillez, J; Yazici, S; Zins, G;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
We present the first optical observation of the microquasar SS 433 at sub-milliarcsecond (mas) scale obtained with the GRAVITY instrument on the Very Large Telescope interferometer (VLTI). The 3.5-h exposure reveals a rich K-band spectrum dominated by hydrogen Br gamma and He i lines, as well as (red-shifted) emission lines coming from the jets. The K-band-continuum-emitting region is dominated by a marginally resolved point source (<1 mas) embedded inside a diffuse background accounting for 10% of the total flux. The jet line positions agree well with the ones expected from the jet kinematic model, an interpretation also supported by the consistent sign (i.e., negative/positive for the receding/approaching jet component) of the phase shifts observed in the lines. The significant visibility drop across the jet lines, together with the small and nearly identical phases for all baselines, point toward a jet that is off set by less than 0.5 mas from the continuum source and resolved in the direction of propagation, with a typical size of 2 mas. The jet position angle of similar to 80 degrees is consistent with the expected one at the observation date. Jet emission so close to the central binary system would suggest that line locking, if relevant to explain the amplitude and stability of the 0.26c jet velocity, operates on elements heavier than hydrogen. The Br gamma profile is broad and double peaked. It is better resolved than the continuum and the change of the phase signal sign across the line on all baselines suggests an East-West-oriented geometry similar to the jet direction and supporting a (polar) disk wind origin.

2017

The wind and the magnetospheric accretion onto the T Tauri star S Coronae Australis at sub-au resolution

Autores
Lopez, RG; Perraut, K; Garatti, ACO; Lazareff, B; Sanchez Bermudez, J; Benisty, M; Dougados, C; Labadie, L; Brandner, W; Garcia, PJV; Henning, T; Ray, TP; Abuter, R; Amorim, A; Anugu, N; Berger, JP; Bonnet, H; Buron, A; Caselli, P; Clenet, Y; du Foresto, VC; de Wit, W; Deen, C; Delplancke Stroebele, F; Dexter, J; Eckart, A; Eisenhauer, F; Dabo, CEG; Gendron, E; Genzel, R; Gillessen, S; Haubois, X; Haug, M; Haussmann, F; Hippler, S; Hubert, Z; Hummel, CA; Horrobin, M; Jocou, L; Kellner, S; Kervella, P; Kulas, M; Kolb, J; Lacour, S; Le Bouquin, JB; Lena, P; Lippa, M; Merand, A; Mueller, E; Ott, T; Panduro, J; Paumard, T; Perrin, G; Pfuhl, O; Ramirez, A; Rau, C; Rohloff, RR; Rousset, G; Scheithauer, S; Schoeller, M; Straubmeier, C; Sturm, E; Thi, WF; van Dishoeck, E; Vincent, F; Waisberg, I; Wank, I; Wieprecht, E; Wiest, M; Wiezorrek, E; Woillez, J; Yazici, S; Zins, G;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Aims. To investigate the inner regions of protoplanetary discs, we performed near-infrared interferometric observations of the classical T Tauri binary system S CrA. Methods. We present the first VLTI-GRAVITY high spectral resolution (R similar to 4000) observations of a classical T Tauri binary, S CrA (composed of S CrAN and S CrA S and separated by similar to 1".4), combining the four 8m telescopes in dual-field mode. Results. Our observations in the near-infrared K-band continuum reveal a disc around each binary component, with similar halfflux radii of about 0.1 au at d similar to 130 pc, inclinations (i = 28 +/- 3 degrees and i = 22 +/- 6 degrees), and position angles (PA = 0 degrees +/- 6 degrees and PA = -2 degrees +/- 12 degrees), suggesting that they formed from the fragmentation of a common disc. The S CrAN spectrum shows bright He i and Br gamma line emission exhibiting inverse PCygni profiles, typically associated with infalling gas. The continuum-compensated Br gamma line visibilities of S CrAN show the presence of a compact Br gamma emitting region whose radius is about similar to 0.06 au, which is twice as big as the truncation radius. This component is mostly tracing a wind. Moreover, a slight radius change between the blue-and red-shifted Br gamma line components is marginally detected. Conclusions. The presence of an inverse PCygni profile in the He i and Br gamma lines, along with the tentative detection of a slightly larger size of the blue-shifted Br gamma line component, hint at the simultaneous presence of a wind and magnetospheric accretion in S CrA N.

2017

Submilliarcsecond Optical Interferometry of the High-mass X-Ray Binary BP Cru with VLTI/GRAVITY

Autores
Waisberg, I; Dexter, J; Pfuhl, O; Abuter, R; Amorim, A; Anugu, N; Berger, JP; Blind, N; Bonnet, H; Brandner, W; Buron, A; Clenet, Y; de Wit, W; Deen, C; Delplancke Strobele, F; Dembet, R; Duvert, G; Eckart, A; Eisenhauer, F; Fedou, P; Finger, G; Garcia, P; Lopez, RG; Gendron, E; Genzel, R; Gillessen, S; Haubois, X; Haug, M; Haussmann, F; Henning, T; Hippler, S; Horrobin, M; Hubert, Z; Jochum, L; Jocou, L; Kervella, P; Kok, Y; Kulas, M; Lacour, S; Lapeyrere, V; Le Bouquin, JB; Lena, P; Lippa, M; Merand, A; Muller, E; Ott, T; Pallanca, L; Panduro, J; Paumard, T; Perraut, K; Perrin, G; Rabien, S; Ramirez, A; Ramos, J; Rau, C; Rohloff, RR; Rousset, G; Sanchez Bermudez, J; Scheithauer, S; Scholler, M; Straubmeier, C; Sturm, E; Vincent, F; Wank, I; Wieprecht, E; Wiest, M; Wiezorrek, E; Wittkowski, M; Woillez, J; Yazici, S;

Publicação
ASTROPHYSICAL JOURNAL

Abstract
We observe the high-mass X-ray binary (HMXB) BP Cru using interferometry in the near-infrared K band with VLTI/GRAVITY. Continuum visibilities are at most partially resolved, consistent with the predicted size of the hypergiant. Differential visibility amplitude (Delta|V| similar to 5%) and phase (Delta phi similar to 2 degrees) signatures are observed across the He I 2.059 mu m and Br gamma lines, the latter seen strongly in emission, unusual for the donor star's spectral type. For a baseline B similar to 100 m, the differential phase rms similar to 0 degrees 2 corresponds to an astrometric precision of similar to 2 mu as. We generalize expressions for image centroid displacements and variances in the marginally resolved limit of interferometry to spectrally resolved data, and use them to derive model-independent properties of the emission such as its asymmetry, extension, and strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high-density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale where accretion takes place, and therefore to probe the effects of the gravitational and radiation fields of the compact object on its environment.

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