Exponential localization of singular vectors in spatiotemporal chaos

In a dynamical system the singular vector (SV) indicates which perturbation will exhibit maximal growth after a time interval $\tau$. We show that in systems with spatiotemporal chaos the SV exponentially localizes in space. Under a suitable transformation, the SV can be described in terms of the Kardar-Parisi-Zhang equation with periodic noise. A scaling argument allows us to deduce a universal power law $\tau^{-\gamma}$ for the localization of the SV. Moreover the same exponent $\gamma$ characterizes the finite-$\tau$ deviation of the Lyapunov exponent in excellent agreement with simulations. Our results may help improving existing forecasting techniques.Comment: 5 page

Avalanche dynamics in fluid imbibition near the depinning transition

We study avalanche dynamics and local activity of forced-flow imbibition fronts in disordered media. We focus on the front dynamics as the mean velocity $\bar{v}$ of the interface is decreased and the pinning state is approached. Scaling arguments allow us to obtain the statistics of avalanche sizes and durations, which become power-law distributed due to the existence of a critical point at $\bar{v}= 0$. Results are compared with phase-field numerical simulations

Time dependent couplings and crossover length scales in non-equilibrium surface roughening

We show that time dependent couplings may lead to nontrivial scaling properties of the surface fluctuations of the asymptotic regime in non-equilibrium kinetic roughening models . Three typical situations are studied. In the case of a crossover between two different rough regimes, the time-dependent coupling may result in anomalous scaling for scales above the crossover length. In a different setting, for a crossover from a rough to either a flat or damping regime, the time dependent crossover length may conspire to produce a rough surface, despite the most relevant term tends to flatten the surface. In addition, our analysis sheds light into an existing debate in the problem of spontaneous imbibition, where time dependent couplings naturally arise in theoretical models and experiments.Comment: Accepted for publication in Physical Review E (Rapid Comm.

“Zombie attack” a new way to teach Chemistry

The Higher Education requires new models which allow training people able to adapt and survive in changing environments. It is based on the use of technologies and the adaptation of knowledge to people. It is about an education according to circumstances, which is adapted to context and virtual behaviour of people. One of the main difficulties that lecturers find in the classroom is how to maintain students' attention and interest in their subject, especially when students also think that the subject is not important for their training. In order to motivate these students, innovation in educational techniques and methodologies, such as experiential learning, are progressively being imposed to and/or coordinated with the traditional ones. Escape Room is a very modern concept in education, based on the development of mental skills for the solution of enigmas and problems. It is a tool to develop the cooperative, cognitive, deductive and logical reasoning skills of the students. In this work, an educational gamification experience based on the escape room concept is presented. The students have 1 hour and 30 minutes to carry out this activity. They will have to solve four puzzles and enigmas that will give them the key to open a treasure chest and finally let them escape from the classroom. Logic, ingenuity and teamwork will allow participants to develop not only chemical competence, but also other basic skills. The story that is told throughout the escape room is a zombie attack: the city has been infected (with a virus) and only the occupants of the room where the activity takes place have not been infected. In addition, they can all protect themselves if they are able to open the chest where the antidote is located. The aim of this activity is to enhance the knowledge acquired throughout the semester as well as the development of skills.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Logarithmic bred vectors in spatiotemporal chaos: structure and growth

Bred vectors are a type of finite perturbation used in prediction studies of atmospheric models that exhibit spatially extended chaos. We study the structure, spatial correlations, and the growth- rates of logarithmic bred vectors (which are constructed by using a given norm). We find that, after a suitable transformation, logarithmic bred vectors are roughly piecewise copies of the leading Lyapunov vector. This fact allows us to deduce a scaling law for the bred vector growth rate as a function of their amplitude. In addition, we relate growth rates with the spectrum of Lyapunov exponents corresponding to the most expanding directions. We illustrate our results with simulations of the Lorenz '96 model.Comment: 8 pages, 8 figure

Sobre algunos elementos del contorno en el diccionario fraseológico

[Resumo] Como é sabido, a lingua conta con dous tipos de unidades léxicas, as monoverbais (as palabras) e as pluriverbais (grande parte das denominadas expresións fixas). Tal consideración supuxo unha paulatina entrada das expresións fixas nos dicionarios de lingua; porén, a diferente natureza das expresións pluriverbais e os elementos do seu contorno teñen reclamado unha metodoloxía particular. Froito disto foi a compilación de dicionarios exclusivamente fraseolóxicos nos que as variantes e os elementos afíns son primordiais. O presente estudo profundiza na necesidade de ir máis alá á hora de detallar os denominados «elementos do contorno », pois estes constitúen verdadeiros signos diacríticos á hora de establecer as diferenzas entre unha unidade e outra.[Resumen] Como se sabe, la lengua cuenta con dos tipos de unidades léxicas, las monoverbales (las palabras) y las pluriverbales (gran parte de las denominadas expresiones fijas). Tal consideración ha supuesto una paulatina entrada de las expresiones fijas en los diccionarios de lengua; sin embargo, la diferente naturaleza de las expresiones pluriverbales y los elementos de su contorno ha reclamado una metodología particular. Fruto de ello ha sido la compilación de diccionarios exclusivamente fraseológicos en los que las variantes y los elementos afines son primordiales. El presente estudio profundiza en la necesidad de ir más allá a la hora de detallar los denominados «elementos del contorno», pues estos constituyen verdaderos signos diacríticos a la hora de establecer las diferencias entre una unidad y otra.[Abstract] Language counts on to types of lexical units, the monoverbal (the word) and the pluriverbal (a considerable part of the fixed phrases). This consideration has opened up for more fixed phrases in dictionaries. However, the differences in the nature of these fixed phrases and the surrounding elements have demanded a particular method. The result of this is the creation of dictionaries of idioms, where the variants and the surrounding elements appear as central elements. The present study is focussing on the necessity of going a step further when we are talking in details about the surrounding elements, as these are the real signs to follow when we want to identify the differences in meaning and the variants of one specific unit

Understanding biological invasions : an experimental study with "Carpobrotus edulis"

[Resumen] Las invasiones biológicas suponen una de las mayores amenazas para la conservación de la biodiversidad a nivel global. Durante los últimos años han sido muchos los trabajos que se han dirigido a intentar conocer los atributos que provocan que una planta se convierta en un invasor agresivo. La plasticidad fenotípica, capacidad de los individuos de ajustar sus respuestas morfológicas y fisiológicas para adaptarse al ambiente, podría ser un atributo clave para entender los procesos de invasión. En este experimento utilizamos individuos de Carpobrotus edulis, una invasora muy agresiva, y Carpobrotus acinaciformis, especie exótica considerada menos agresiva, para comparar su plasticidad en términos de distribución de recursos ante la presencia de distintos niveles de nutrientes. Nuestro trabajo muestra que existen diferencias significativas en la cantidad de raíz producida por C. edulis y C. acinaciformis en función del contenido de nutrientes del suelo, con C. edulis mostrando una mayor plasticidad para este carácter. Este resultado parece apoyar la idea de que la plasticidad fenotípica podría contribuir al éxito de algunas especie invasoras.[Resumo] As invasións biolóxicas supoñen unha das maiores ameazas para a conservación da biodiversidade a nivel global. Durante os últimos anos, moitos traballos tentaron descubrir os atributos que fan que unha planta se converta nun invasor agresivo. A plasticidade fenotípica, capacidade dos individuos da axustar as súas respostas morfolóxicas e fisiolóxicas para adaptarse ó ambiente, podería ser un atributo clave para comprender os procesos de invasión. Neste experimento utilizamos individuos de Carpobrotus edulis, unha invasora moi agresiva, e Carpobrotus acinaciformis, especie exótica considerada coma menos agresiva, para Página 2 de 23 comparar a súa plasticidade atendendo á distribución de recursos da planta en función da presencia de distintos niveis de nutrientes. O noso traballo mostra que existen diferencias significativas na cantidade de raíz producida por C.edulis e C.acinaciformis en función do contido de nutrintes do solo, mostrando C.edulis unha maior plasticidade para este caracter. Iste resultado parece apoiar a idea de que a plasticidade fenotípica podería contribuir ó éxito dalgunhas especies invasoras.[Abstract] Biological invasions are one of the biggest threats to global biodiversity conservation. In recent years there has been many essays focused on discovering which characteristics make a plant become an aggressive invader. Phenotypic plasticity -ability of an individual to adjust their morphological and physiological responses in order to adapt to the environment- could be a key attribute in order to understand invasion processes. In this experiment we use individuals of C.edulis (very aggressive invader) and C.acinaciformis (exotic species, less aggressive invader) in order to compare their plasticity in terms of resources distribution in presence of different soil nutrient concentrations. Our essay shows significative differences in root mass produced by C.edulis and C.acinaciformis depending on the content in soil nutrients, C.edulis showed a higher plasticity for this character. This result seems to support the idea that phenotypic plasticity could contribute to the success of some invasive species.Traballo fin de grao (UDC.CIE). Bioloxía. Curso 2014/201

Bone artifacts from chalcolithic funerary contexts in the eastern and southeastern Iberia: pointed flat rods

Uno de los objetos óseos más característicos del registro funerario del Neolítico y Calcolítico del Sureste de la península Ibérica son las llamadas “varillas planas de hueso”. Con este nombre es con el que mayoritariamente se las viene conociendo en la bibliografía arqueológica desde inicios del siglo xx. No obstante, su identificación, descripción y atribución funcional nunca han dejado de suponer un problema. Este trabajo se centra en el análisis de las técnicas de trabajo empleadas en su producción y en evaluar las diferentes hipótesis planteadas en cuanto a su posible uso como agujas para el pelo, alfileres o paletines cosméticos, entre otras, a partir de los contextos arqueológicos documentados en excavaciones recientes y en el análisis de antiguas colecciones conservadas en diversos museos.One of the most characteristic bone objects in the Late Neolithic and Chalcolithic funerary record of the south-eastern area of the Iberian Peninsula is the so-called “pointed flat rod”. They have been mentioned in many of the papers published since the beginning of the 20th century. However, their identification, description and functional attribution have not ceased to be problematic. This paper has focused in the manufacturing techniques employed in the production of these bone artefacts and evaluates the different hypotheses related to their supposed use as hairpins, awls or cosmetic palettes —among others— taking into account the archaeological contexts recorded in some recent excavations and the analysis of ancient collections stored in museums