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San Luis Potosí, Mexico

Afraimovich V.,IICO UASLP | Young T.,Ohio University | Muezzinoglu M.K.,University of California at San Diego | Rabinovich M.I.,University of California at San Diego
Bulletin of Mathematical Biology | Year: 2011

Emotion (i. e., spontaneous motivation and subsequent implementation of a behavior) and cognition (i. e., problem solving by information processing) are essential to how we, as humans, respond to changes in our environment. Recent studies in cognitive science suggest that emotion and cognition are subserved by different, although heavily integrated, neural systems. Understanding the time-varying relationship of emotion and cognition is a challenging goal with important implications for neuroscience. We formulate here the dynamical model of emotion-cognition interaction that is based on the following principles: (1) the temporal evolution of cognitive and emotion modes are captured by the incoming stimuli and competition within and among themselves (competition principle); (2) metastable states exist in the unified emotion-cognition phase space; and (3) the brain processes information with robust and reproducible transients through the sequence of metastable states. Such a model can take advantage of the often ignored temporal structure of the emotion-cognition interaction to provide a robust and generalizable method for understanding the relationship between brain activation and complex human behavior. The mathematical image of the robust and reproducible transient dynamics is a Stable Heteroclinic Sequence (SHS), and the Stable Heteroclinic Channels (SHCs). These have been hypothesized to be possible mechanisms that lead to the sequential transient behavior observed in networks. We investigate the modularity of SHCs, i. e., given a SHS and a SHC that is supported in one part of a network, we study conditions under which the SHC pertaining to the cognition will continue to function in the presence of interfering activity with other parts of the network, i. e., emotion. © 2010 The Author(s). Source


Rivera-Perez E.,University of Valencia | Diez A.,University of Valencia | Andres M.V.,University of Valencia | Cruz J.L.,University of Valencia | Rodriguez-Cobos A.,IICO UASLP
Optics Letters | Year: 2013

Narrowband filtering based on whispering gallery modes of a slightly tapered cylindrical optical microresonator was used to implement a tunable narrowband erbium-doped fiber laser. The laser can be set to emit a single longitudinal cavity mode (single frequency), although the laser cavity is a few meters long. In the single-frequency regime the laser can emit a maximumpower of 0.380mWwith a linewidth <35 kHz and a signal-to-noise ratio exceeding 50 dB. Tunability is achieved by sliding the excitation point along the microcylinder. A tuning range of 1.16 nm is demonstrated. © 2013 Optical Society of America. Source


Rivera-Perez E.,University of Valencia | Diez A.,University of Valencia | Andres M.V.,University of Valencia | Cruz J.L.,University of Valencia | Rodriguez-Cobos A.,IICO UASLP
2013 Conference on Lasers and Electro-Optics Europe and International Quantum Electronics Conference, CLEO/Europe-IQEC 2013 | Year: 2013

Optical microresonators (MR) exhibit a unique combination of high quality factor [1], small mode volume, and good mechanical stability that make these systems of interest for a number of photonics applications, such as narrowband lasers [2] and sensors. Silica microspheres, microdisks and toroids have been used for different applications. Recently, a series of studies using cylindrical MRs as microcylinders and microcapillaries have been reported [3], showing tuning capacities either as a function of the diameter, using tapered fibres, or as a function of the refractive index filling the capillaries. Such tuning capabilities are unable in the case of using other type of MR as for example microspheres. © 2013 IEEE. Source


Momox Beristain E.,CIDS ICUAP BUAP | Olvera-Hernandez J.,CIDS ICUAP BUAP | Martinez-Juarez J.,CIDS ICUAP BUAP | De Anda F.,IICO UASLP | And 4 more authors.
Thin Solid Films | Year: 2011

It is shown experimentally that the thickness and composition of Ga 1 - xAlxSb layers grown by liquid phase epitaxy on Gasb substrates depend on the conductivity type of the substrates. To avoid experimental uncertainties that naturally happen from an experiment to another one, such as changes in the exact liquid composition, growth temperature, temperature gradients, etc., the Ga1 - xAlxSb layers have been grown simultaneously from the same liquid solution on N and P type GaSb substrates. The X-ray rocking curves show that for every couple of layers, grown on N and P type substrates, there is a consistent difference between their thickness and composition. The thickness difference has also been verified by optical microscopy. A likely explanation of this effect is a change in surface energy of the substrate induced by the surface electric field normally present in semiconductors. © 2010 Elsevier B.V. All rights Reserved. Source


Afraimovich V.,IICO UASLP | Cuevas D.,IICO UASLP | Young T.,Ohio University
Dynamical Systems | Year: 2013

Following on previous work, we discuss a scenario in which two neural ensembles have a master-slave arrangement. We will consider a more particular case in which the master system exhibits transient dynamics due to a stable heteroclinic sequence (SHS) and the slave system has attractors in the form of limit cycles. We will give sufficient conditions that guarantee the existence of a SHS in the form of a tube in the full phase space, together with an open stable heteroclinic channel that surrounds it. We present a numerical observation of chaotic-like transient behaviour different from well-known transient chaos. © 2013 Taylor and Francis Group, LLC. Source

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