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Samuel Chiquita

Publications and source records attributed to Samuel Chiquita.

2 recordsLinked to original sources
arXiv2018

Monte Carlo simulation of 192Ir radioactive source in a phantom designed for brachytherapy dosimetry and source position evaluation

In this report simulations of 192Ir source located inside a phantom designed for measuring the absorbed dose and radioactive source position are presented. Monte Carlo simulations were performed and results were compared with a theoretical model that enables to determine radioactive source position. A good fit from the simulated data to the theoretical model was obtained. Results show that Monte Carlo simulations allow to evaluate source position and absorbed dose with implications in treatment planning.

physics.med-ph↗
arXiv2018

A theoretical framework for retinal computations: insights from textbook knowledge

Neural circuits in the retina divide the incoming visual scene into more than a dozen distinct representations that are sent on to central brain areas, such as the lateral geniculate nucleus and the superior colliculus. The retina can be viewed as a parallel image processor made of a multitude of small computational devices. Neural circuits of the retina are constituted by various cell types that separate the incoming visual information in different channels. Visual information is processed by retinal neural circuits and several computations are performed extracting distinct features from the visual scene. The aim of this article is to understand the computational basis involved in processing visual information which finally leads to several feature detectors. Therefore, the elements that form the basis of retinal computations will be explored by explaining how oscillators can lead to a final output with computational meaning. Linear versus nonlinear systems will be presented and the retina will be placed in the context of a nonlinear system. Finally, simulations will be presented exploring the concept of the retina as a nonlinear system which can perform understandable computations converting a known input into a predictable output.

q-bio.NC↗