Alessandro J. De Souza

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OBJECTIVE This study used image processing techniques to quantify the upper eyelid contour of patients with Graves upper eyelid retraction and congenital blepharoptosis. DESIGN The study design was a cross-sectional study. PARTICIPANTS A total of 29 patients with Graves disease, 22 patients with congenital blepharoptosis, and 50 patients with no history(More)
Context. As is the case of several other Be stars, Achernar is surrounded by an envelope, recently detected by near-IR interferometry. Aims. We search for the signature of circumstellar emission at distances of a few stellar radii from Achernar, in the thermal IR domain. Methods. We obtained interferometric observations on three VLTI baselines in the N band(More)
Differential interferometry (DI) is a technique that combines high spectral resolution with high spatial resolution. It is particularly suited to probe mechanisms that induce chromatic signatures, such as large scale mass motions. We thus investigate the use of DI combined with the Fourier transform method to study the stellar surface differential rotation.(More)
In this work, an atomic force microscope (AFM) is combined with a confocal Raman spectroscopy setup to follow in situ the evolution of the G-band feature of isolated single-wall carbon nanotubes (SWNTs) under transverse deformation. The SWNTs are pressed by a gold AFM tip against the substrate where they are sitting. From eight deformed SWNTs, five exhibit(More)
Several interferometric observations revealed that the rapid rotator Altair is a flattened star with a non-centrally symmetric intensity distribution. In this work we perform for the first time a physically consistent analysis of all interferometric data available so far, corresponding to three different interferometers operating in several spectral bands.(More)
Context. The star HD 87643, exhibiting the " B[e] phenomenon " , has one of the most extreme infrared excesses for this object class. It harbours a large amount of both hot and cold dust, and is surrounded by an extended reflection nebula. Aims. One of our major goals was to investigate the presence of a companion in HD87643. In addition, the presence of(More)
This paper presents the results of 30 years of water quality monitoring in a tropical water supply reservoir (Vargem das Flores, Brazil). This water body is subjected to eutrophication problems caused by point sources (discharge of untreated sewage) and diffuse pollution (agricultural use in the drainage basin). Emphasis is given here on the estimation of(More)
HD 50138 is a B[e] star surrounded by a large amount of circumstellar gas and dust. Its spectrum shows characteristics which may indicate either a pre-or a post-main-sequence system. Mapping the kinematics of the gas in the inner few au of the system contributes to a better understanding of its physical nature. We present the first high spatial and spectral(More)