Space-time nature of causality

Peer reviewedPostprintPublisher PD

Symbolic computations of non-linear observability

Date of Acceptance: 22/05/2015 ACKNOWLEDGEMENTS E.B.M. and M.S.B. acknowledge the Engineering and Physical Sciences Research Council (EPSRC), Grant No. EP/I032608/1. This work was done during a stay of E.B.M. at CORIA (Rouen) and a stay of C.L. at ICSMB (Aberdeen).Peer reviewedPublisher PD

A symbolic network-based nonlinear theory for dynamical systems observability

EBM and MSB acknowledge the Engineering and Physical Sciences Research Council (EPSRC), grant Ref. EP/I032608/1. ISN acknowledges partial support from the Ministerio de Economía y Competitividad of Spain under project FIS2013-41057-P and from the Group of Research Excelence URJC-Banco de Santander.Peer reviewedPublisher PD

Exact detection of direct links in networks of interacting dynamical units

Authors NR, EB-M, CG, and MSB acknowledge the Scottish Universities Physics Alliance (SUPA). EB-M and MSB also acknowledge the Engineering and Physical Science Research Council (EPSRC) project Ref. EP/I032 606/1. ACM and CM acknowledge the LINC project (FP7-PEOPLE-2011-ITN, grant no. 289447). ACM also aknowledges PEDECIBA and CSIC(Uruguay). CM also acknowledges grant FIS2012–37655-C02–01 from the Spanish MCI, grant 2009 SGR 1168, and the ICREA Academia programme from the Generalitat de Catalunya.Peer reviewedPublisher PD

Descripción bibliográfica de funciones trascendentes y su aplicación en las ciencias biológicas

Es de fundamental importancia para el desarrollo de las capacidades de los estudiantes, incentivarlos en el hábito de la lectura comprensiva y orientarlos en las correspondientes consultas bibliográficas a fin de que afiancen sus conocimientos. Nuestro objetivo estuvo centrado en conocer el tratamiento de las funciones logarítmicas y exponenciales en bibliografía de los niveles Polimodal y Universitario, desde su presentación, la utilización de los diferentes registros y la respectiva conversión de los mismos, hasta los ejemplos y ejercicios de aplicación que se encuentran en ellos. Haciendo una selección precisa de textos de uno u otro nivel y orientando a los alumnos en la elección de los mismos, encontrarán un complemento significativo de las clases teóricas prácticas del tema que les facilitará su aprendizaje y posterior aplicación

Objetos matemáticos y registros semióticos para un aprendizaje significativo

El presente trabajo se circunscribe a una propuesta de enseñanza implementada en la Facultad de Ciencias Exactas y Naturales de la Universidad Nacional de La Pampa, con alumnos de primer año de Química y Biología que durante el ciclo académico 2010 cursaban Matemática. Utilizando la plataforma Moodle y los recursos que provee el software GeoGebra se diseñó e implementó una estrategia didáctica para el desarrollo del tema Secciones Cónicas, correspondiente a una de las unidades del programa de esta asignatura. El proceso de contextualizar objetos matemáticos en situaciones de enseñanza – aprendizaje, no sólo se consolida con la automatización de ciertos tratamientos o la comprensión de nociones, sino que implica una coordinación de registros de representación. Un sujeto comprende el significado de un determinado concepto si,por ejemplo es capaz de reconocer sus propiedades y representaciones características, establecer relaciones con otros objetos y aplicarlo en diversas situaciones problemáticas. Los docentes que participamos en esta propuesta consideramos que a futuro realizaremos acciones de características similares en otros contenidos, reflexionando sobre nuestra práctica docente y con el objeto de favorecer el aprendizaje de esta disciplina con alumnos de carreras no matemáticas

In-situ pulsed laser induced growth of CdS nanoparticles on ZnO nanorods surfaces

Herein we present a process for the in-situ growth of CdS nanoparticles using a pulsed laser irradiation. A Nd-YAG laser was applied to ZnO nanorods previously submerged in an aqueous precursor solution containing cadmium chloride and thiourea. For optimum values of the laser fluence, around 40 mJ/cm2 it was possible to fabricate a highly homogeneous film of CdS nanoparticles covering the ZnO nanorods surface. Cathodoluminescence measurements of the ZnO/CdS structure show the quenching of the ZnO yellow and green luminescence, indicating the ZnO surface defects passivation by CdS nanostructures. Although lasers have been already used for inducing growth in solution, this work presents new evidence of in-situ growth on the surface of nanostructured materials. The laser based technique presented is simple, easy to implement, scalable and it could be applied in the fabrication of nanostructured solar cells and other devices

Successful network inference from time-series data using Mutual Information Rate

This work uses an information-based methodology to infer the connectivity of complex systems from observed time-series data. We first derive analytically an expression for the Mutual Information Rate (MIR), namely, the amount of information exchanged per unit of time, that can be used to estimate the MIR between two finite-length low-resolution noisy time-series, and then apply it after a proper normalization for the identification of the connectivity structure of small networks of interacting dynamical systems. In particular, we show that our methodology successfully infers the connectivity for heterogeneous networks, different time-series lengths or coupling strengths, and even in the presence of additive noise. Finally, we show that our methodology based on MIR successfully infers the connectivity of networks composed of nodes with different time-scale dynamics, where inference based on Mutual Information fails

Evaluating performance of neural codes in model neural communication networks

Information needs to be appropriately encoded to be reliably transmitted over physical media. Similarly, neurons have their own codes to convey information in the brain. Even though it is well-known that neurons exchange information using a pool of several protocols of spatio-temporal encodings, the suitability of each code and their performance as a function of network parameters and external stimuli is still one of the great mysteries in neuroscience. This paper sheds light on this by modeling small-size networks of chemically and electrically coupled Hindmarsh-Rose spiking neurons. We focus on a class of temporal and firing-rate codes that result from neurons' membrane-potentials and phases, and quantify numerically their performance estimating the Mutual Information Rate, aka the rate of information exchange. Our results suggest that the firing-rate and interspike-intervals codes are more robust to additive Gaussian white noise. In a network of four interconnected neurons and in the absence of such noise, pairs of neurons that have the largest rate of information exchange using the interspike-intervals and firing-rate codes are not adjacent in the network, whereas spike-timings and phase codes (temporal) promote large rate of information exchange for adjacent neurons. If that result would have been possible to extend to larger neural networks, it would suggest that small microcircuits would preferably exchange information using temporal codes (spike-timings and phase codes), whereas on the macroscopic scale, where there would be typically pairs of neurons not directly connected due to the brain's sparsity, firing-rate and interspike-intervals codes would be the most efficient codes

Spectroscopy near the proton drip line in the deformed A=130 mass region : the Pr-126 nucleus

The near proton drip line nucleus Pr-126 was studied via in-beam gamma-ray spectroscopy using the Ca-40 + Mo-92 reaction at 190 MeV. We observed for the first time excited states above the known isomer in this nucleus up to 31 h over bar. The observed band is discussed in the interacting boson-fermion-fermion model.The calculations and the experimental information suggest a spin 8(+) for the lowest observed state.With such a spin assignment the moment of inertia of Pr-126 gets larger than in the heavier Pr isotopes, suggesting a sudden change in deformation close to the proton drip line