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Aboites V.,Center for Research in Optics | Pisarchik A.N.,Center for Research in Optics | Kiryanov A.,Center for Research in Optics | Gomez-Mont X.,Center for Research in Mathematics
Optics Communications | Year: 2010

In this article the dynamical behavior of a beam within a ring-phase-conjugated resonator is modeled using two-dimensional iterative maps. In particular and as an example it is explicitly shown how the difference equations of the Duffing map can be used to describe the dynamic behavior of what we call Duffing beams i.e. beams that behave according to the Duffing map. The matrix of a Duffing map generating device is found in terms of the Duffing parameters, the state variables and the resonator parameters. To our knowledge this is the first time that the mathematical characteristics of an optical device in an optical cavity are stated so that a Duffing map is obtained as the dynamics for the ray beams. © 2010 Elsevier B.V. All rights reserved.


Sanchez-Marin F.J.,Center for Research in Optics | Padilla-Medina J.A.,Celaya Institute of Technology
Computers in Biology and Medicine | Year: 2010

Simple reaction times (SRT) to visual stimuli were investigated through reactions to computer simulations of changes of traffic lights. The performance in the detection of visual stimuli, implying decision processes, was also assessed using the two alternative forced choice (2AFC) method. Subjects were patients affected by diabetes type 2, and observers without diabetes. Results indicated that mean SRT was longer in the group of diabetic patients but was not correlated with age, diabetes duration or fasting glucose. The performance index (d') was correlated with age and with diabetes duration. Unexpectedly, the correlation between fasting glucose and d' was not negative. © 2010 Elsevier Ltd.


Campos-Lopez J.P.,National Polytechnic Institute of Mexico | Campos-Lopez J.P.,Polytechnic University of the Valley of Mexico | Fuerte-Hernandez A.,National Polytechnic Institute of Mexico | Hernandez-Gomez L.H.,National Polytechnic Institute of Mexico | And 3 more authors.
Journal of Applied Biomaterials and Functional Materials | Year: 2015

Purpose: To evaluate the strain fields and to calculate the modulus of elasticity and Poisson’s ratio of trabecular bone of the 6 lumbar vertebrae of the porcine spine by a 2-dimensional digital image correlation (2D DIC). Methods: This study was performed through a 2D DIC technique and the specimens were tested under compression. The resulting images were analyzed numerically by 2D DIC. Then, representative regions of interest were examined. The strain fields were determined and stress-strain curves were obtained. Results: The full field measurement of the strain in the lumbar bone spine was evaluated and with this data, the Young’s modulus and Poisson’s ratio were determined. Conclusions: This research highlights the potential applications of noninvasive acquisition techniques in biomechanical analysis. This is useful in the mechanical characterization of bony structures and in the design of prostheses. © 2015 Wichtig Publishing.


Aboites V.,Center for Research in Optics | Barmenkov Y.O.,Center for Research in Optics | Kir'yanov A.,Center for Research in Optics | Wilson M.,Center for Research in Optics
Results in Physics | Year: 2012

In this article the dynamical behaviour of a beam that behaves according to a Tinkerbell map (i.e. Tinkerbell beam), within a nonlinear ring phase-conjugated resonator is modelled. The ABCD matrix of an optical device able to generate a two dimensional Tinkerbell map is found in terms of the map parameters, the state variables and the resonator parameters. For the first time to our knowledge the conditions in order to obtain the dynamics of a beam behaving according to a Tinkerbell map are found within an optical resonator. Finally some of the main technical problems to build a resonator intracavity element able to produce Tinkerbell beams are presented. © 2012 Elsevier B.V.


PubMed | Center for Research in Optics
Type: Journal Article | Journal: Perceptual and motor skills | Year: 2011

Plateaus experiment, in which the bisection method was introduced, is recognized as the first psychophysical experiment ever done. That experiment was replicated and extended using modem imaging devices. First, participants with professional training in visual arts painted grayscales with no control on illumination. Then, the trained participants and the nontrained participants generated grayscales using a personal computer in three different conditions: a white background of a linearized monitor, a black background of that monitor, and a white background but without linearizing the monitor. Analyses showed that with artificial illumination, scales with steps more evenly spread were produced than with natural illumination. Humans do not seem to have a natural ability to use the bisection method properly. Experts seem to be able to judge the reflectance of distal stimuli, and perceptual learning played an important role in the perception of achromatic colors as found in prior literature.


PubMed | Center for Research in Optics and National Polytechnic Institute of Mexico
Type: Journal Article | Journal: Journal of applied biomaterials & functional materials | Year: 2015

To evaluate the strain fields and to calculate the modulus of elasticity and Poissons ratio of trabecular bone of the 6 lumbar vertebrae of the porcine spine by a 2-dimensional digital image correlation (2D DIC).This study was performed through a 2D DIC technique and the specimens were tested under compression. The resulting images were analyzed numerically by 2D DIC. Then, representative regions of interest were examined. The strain fields were determined and stress-strain curves were obtained.The full field measurement of the strain in the lumbar bone spine was evaluated and with this data, the Youngs modulus and Poissons ratio were determined.This research highlights the potential applications of noninvasive acquisition techniques in biomechanical analysis. This is useful in the mechanical characterization of bony structures and in the design of prostheses.

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