Luis F. M. S. Silva

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Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage(More)
Metaplasia, in general, and intestinal metaplasia, in particular, are transdifferentiation processes triggered by environmental aggressions. The heterogeneity of different morphologic variants of metaplasia and distinction from close morphologic entities--heterotopia and hamartoma--is reviewed. Recent data on the characterization of the molecular and(More)
In this work we propose a method for converting triangular meshes into LEGO bricks through a voxel representation of boundary meshes. We present a novel voxelization approach that uses points sampled from a surface model to define which cubes (voxels) and their associated colors will compose the model. All steps of the algorithm were implemented on the GPU(More)
The exploration of 3D environments using 6 degrees-of-freedom interaction is still a challenge since users easily become disoriented. In this paper we discuss the benefits of the whole-body awareness in 3D interactive applications. We propose a technique for navigation and selection in 3D environments which explores the peephole metaphor with a tablet PC.(More)
The flow rates of drying and nebulizing gas, heat block and desolvation line temperatures and interface voltage are potential electrospray ionization parameters as they may enhance sensitivity of the mass spectrometer. The conditions that give higher sensitivity of 13 pharmaceuticals were explored. First, Plackett-Burman design was implemented to screen(More)
Inventories and vertical distribution of (137)Cs were determined in La Plata region undisturbed soils, Argentina. A mean inventory value of 891 ± 220 Bq/m(2) was established, which is compatible with the values expected from atmospheric weapon tests fallout. The study was complemented with pH, organic carbon fraction, texture and mineralogical soil(More)
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