Robust synchronization of a class of uncertain complex networks via discontinuous control

AbstractWe propose robust controller designs to synchronize networks with uncertainties in their node dynamics and their connections. We consider two situations: in the first, we assume that the effect of uncertainties vanishes as synchronization is achieved. In the second, disturbances are assume nonvanishing but bounded. To achieve robust synchronization on these situations, we design local feedback controllers, which are smooth in the first case, and discontinuous in the latter. These designs allow us to establish synchronization criteria for this class of uncertain dynamical networks. We use numerical experiments to illustrate our results

Activation of neuronal ensembles via controlled synchronization

"In this contribution we present the activation of neuronal ensembles of Hindmarsh-Rose neurons by controlled synchronization. The main problem consists in to impose a particular spiking-bursting behavior in all the neurons of the network. We consider a network where the neurons are in its resting state, it is desired that the neurons change their resting state to a particular behavior of activation, dictated by a neuron called the reference neuron. The goal is reached by controlling some neurons in the network controlling only the membrane potential (electrical synapse). The key feature of the present contribution is that by controlling a small number of neurons in the network a desired behavior is induced in all the neurons in the network despite its network topology. The important parameters are the control gain and the coupling strength, thus the activation of the network lays down on a compromise between the control gain and the coupling strength.

On the emergence of chaos in dynamical networks

"We investigate how changes of specific topological features result on transitions among different bounded behaviours in dynamical networks. In particular, we focus on networks with identical dynamical systems, synchronised to a common equilibrium point, then a transition into chaotic behaviour is observed as the number of nodes and the strength of their coupling changes. We analyse the network's transverse Lyapunov exponents (tLes) to derive conditions for the emergence of bounded complex behaviour on different basic network models. We find that, for networks with a given number of nodes, chaotic behaviour emerges when the coupling strength is within a specific bounded interval; this interval is reduced as the number of nodes increases. Furthermore, the endpoints the emergence interval depend on the coupling structure of network. We also find that networks with homogeneous connectivity, such as regular lattices and small-world networks are more conducive to the emergence of chaos than networks with heterogeneous connectivity like scale-free and star-connected graphs. Our results are illustrated with numerical simulations of the chaotic benchmark Lorenz systems, and to underline their potential applicability to real-world systems, our results are used to establish conditions for the chaotic activation of a network of electrically coupled pancreatic β-cell models.

On the controllability of networks with nonidentical linear nodes

"The controllability of dynamical networks depends on both network structure and node dynamics. For networks of linearly coupled linear dynamical systems the controllability of the network can be determined using the well-known Kalman rank criterion. In the case of identical nodes the problem can be decomposed in local and structural contributions. However, for strictly different nodes an alternative approach is needed. We decomposed the controllability matrix into a structural component, which only depends on the networks structure and a dynamical component which includes the dynamical description of the nodes in the network. Using this approach we show that controllability of dynamical networks with strictly different linear nodes is dominated by the dynamical component. Therefore even a structurally uncontrollable network of different nn dimensional nodes becomes controllable if the dynamics of its nodes are properly chosen. Conversely, a structurally controllable network becomes uncontrollable for a given choice of the node’s dynamics. Furthermore, as nodes are not identical, we can have nodes that are uncontrollable in isolation, while the entire network is controllable, in this sense the node’s controllability is overwritten by the network even if the structure is uncontrollable. We illustrate our results using single-controller networks and extend our findings to conventional networks with large number of nodes.

Sexo, tipología de género, erotofilia-erotofobia y asertividad sexual en estudiantes universitarios

Objetivo y Método de Estudio: Determinar la influencia que tiene el sexo, tipología de género y erotofilia-erotofobia en la asertividad sexual en estudiantes universitarios. La población fueron jóvenes de 18 a 25 años de una Universidad Privada del Área Metropolitana de Monterrey, Nuevo León. El tamaño de la muestra se calculó para una prueba de regresión lineal múltiple considerando cuatro variables independientes con una confiabilidad del 95%, potencia de prueba del 90% y coeficiente de correlación de .09. El tamaño de la muestra fue de 317 jóvenes, los cuales se seleccionaron por un muestreo por conglomerados unietápico donde los conglomerados fueron 22 de los 50 grupos de la Universidad Privada. Se utilizaron tres instrumentos de medición con confiabilidad aceptable. El análisis se basó en estadística descriptiva, la prueba de Kolmogorov-Smirnov (K-S) con corrección de Lilliefors, prueba de Kruskal-Wallis, coeficiente de correlación de Spearman y modelos de Regresión Lineal con estadístico de contraste Bootstrap. Conclusiones y Contribuciones: Los participantes fueron en su mayoría hombres (55.6%) y la edad media fue 21.15 años (DE = 2.09). Los jóvenes se identifican mayormente con atributos socioculturales de rasgos masculinos (M = 5.24, DE = .69) que con atributos de rasgos femeninos (M = 4.84, DE = .75). Más de la mitad de los estudiantes son erotofílicos (M = 62.17, DE = 23.34). El promedio de asertividad sexual en los universitarios se ubicó en un nivel medio (M = 60.52, DE = 14.87). Se encontró que el sexo influye sobre la asertividad sexual (B = 11.92, p < .001) y la erotofiliaerotofobia (B = -9.60, p < .001). Se ajustó un modelo que consideró tres de las cuatro variables (F [3, 271] = 20.78, p < .001), explicando la varianza en 17.8%. Los modelos de regresión para erotofilia-erotofobia no resultaron significativos. Estos resultados son de gran importancia para la enfermería, ya que aportan una perspectiva de género sobre la asertividad sexual, lo cual permite buscar y desarrollar estrategias para que los jóvenes conozcan la importancia de la asertividad sexual y al mismo tiempo se consideren sus conductas a partir de una construcción social

Nanomedicina como innovación tecnológica de interés en el tratamiento del cáncer

El cáncer supone un desafío para la farmacoterapia actual. El desarrollo de la nanomedicina es una de las líneas de investigación en la que más esfuerzos se invierten en el ámbito de la tecnología farmacéutica. Estos nanosistemas posibilitan la vectorización de fármacos a las células o tejidos diana, permitiendo así una acción más específica y dirigida de las moléculas con actividad terapéutica. El campo de la oncología es el mejor sujeto en el que emplear estas estrategias terapéuticas, por ello en este trabajo se aborda la nanomedicina desde esta perspectiva, centrándonos en el cáncer de mama. La vectorización de nanoestructuras que sean capaces de llegar a la masa tumoral de una forma más eficaz, segura y con menores efectos secundarios es lo que se persigue en esta revisión. Por último, analizamos un ejemplo de innovación tecnológica aplicado al cáncer de mama basado en nanopartículas de paclitaxel con albúmina, cuyo uso está actualmente aprobado en clínica

Lie algebra on synchronization of different systems: a generalized function for Hodgkin-Huxley neurons

"In this contribution two results are taken: (1) The synchronization of noiseless Hodgkin- Huxley (HH) neurons is possible from robust feedback based on Lie algebra approaches and (2) the fact that, from Lie algebra of vector fields, the generalized synchronization of different (triangular form) chaotic systems can be used to derive an explicit synchronization function. Both results are extended to derive the synchronization function in HH neurons despite this systems are not in triangular form. Thus, the Lie algebra of vectors fields permits to establish a theoretical framework for finding the synchroniza- tion function in chaotic systems in face they have different model.