Bolitoglossa spongai

Number of Pages: 2Integrative BiologyGeological Science

Kneadings, Symbolic Dynamics and Painting Lorenz Chaos. A Tutorial

A new computational technique based on the symbolic description utilizing kneading invariants is proposed and verified for explorations of dynamical and parametric chaos in a few exemplary systems with the Lorenz attractor. The technique allows for uncovering the stunning complexity and universality of bi-parametric structures and detect their organizing centers - codimension-two T-points and separating saddles in the kneading-based scans of the iconic Lorenz equation from hydrodynamics, a normal model from mathematics, and a laser model from nonlinear optics.Comment: Journal of Bifurcations and Chaos, 201

Rhythmic firing patterns in SCN: The role of circuit interactions

The suprachiasmatic nucleus (SCN) is believed to contain the main generator of circadian rhythmicity in mammals. In order to obtain further functional details of this, electrophysiological extracellular measurements in vitro were made. By means of an interspike interval distribution analysis, it is shown that there is a novel kind of neuronal firing pattern: the harmonic pattern. From these observations, we have developed a theoretical model based on possible filtering processes occurring during synaptic transmission. The model suffices to infer that regular ultradian oscillators could be an emergent property of circuit interactions of cells in the suprachiasmatic nucleus

How to generate pentagonal symmetry using Turing systems

We explore numerically the formation of Turing patterns in a confined circular domain with small aspect ratio. Our results show that stable fivefold patterns are formed over a well defined range of disk sizes, offering a possible mechanism for inducing the fivefold symmetry observed in early development of regular echinoids. Using this pattern as a seed, more complex biological structures can be mimicked, such as the pigmentation pattern of sea urchins and the plate arrangements of the calyxes of primitive camerate crinoids

On the taxonomy of snakes in the genus Leptodeira, with an emphasis on Costa Rican species

Considerable confusion surrounds the taxonomy of snakes in the genus Leptodeira, which contains 12 currently recognized species. Herein I review the genus and recognize 15 species based on previously published morphological and genetic data. Easily recognized traits can be used to identify Costa Rican species of Leptodeira, and taxonomic insights into all species in the L. annulata-septentrionalis complex are discussed. Photographs of all currently recognized species and subspecies are included

Non-linear effects on Turing patterns: time oscillations and chaos.

We show that a model reaction-diffusion system with two species in a monostable regime and over a large region of parameter space, produces Turing patterns coexisting with a limit cycle which cannot be discerned from the linear analysis. As a consequence, Turing patterns oscillate in time, a phenomenon which is expected to occur only in a three morphogen system. When varying a single parameter, a series of bifurcations lead to period doubling, quasi-periodic and chaotic oscillations without modifying the underlying Turing pattern. A Ruelle-Takens-Newhouse route to chaos is identified. We also examined the Turing conditions for obtaining a diffusion driven instability and discovered that the patterns obtained are not necessarily stationary for certain values of the diffusion coefficients. All this results demonstrates the limitations of the linear analysis for reaction-diffusion systems

Ventajas de la uniformización de objetos didácticos para la mejora de resultados docentes en un máster interuniversitario

El uso de entornos virtuales por parte de las universidades españolas está realmente consolidado, en ellos el docente puede poner a disposición de su alumnado diferentes tipos de objetos didácticos con los contenidos docentes de una determinada asignatura. Es evidente que el contenido de dichos objetos didácticos es importante para adquirir las competencias necesarias, pero también hay que poner atención al formato de los mismos. El presente trabajo pretende poner de manifiesto la importancia de la uniformización de objetos didácticos en la mejora de los resultados docentes. Este aspecto es especialmente relevante cuando se trata de estudios interuniversitarios, en los que intervienen docentes de diferentes universidades y con diferentes plataformas virtuales para generar y poner a disposición del alumnado el material didáctico. En particular se ha empleado la información disponible del Máster interuniversitario en Integridad y Durabilidad de Materiales, Componentes y Estructuras impartido conjuntamente por las Universidades de Oviedo, Cantabria y Burgos