Self-pulsing dynamics of ultrasound in a magnetoacoustic resonator

A theoretical model of parametric magnetostrictive generator of ultrasound is considered, taking into account magnetic and magnetoacoustic nonlinearities. The stability and temporal dynamics of the system is analized with standard techniques revealing that, for a given set of parameters, the model presents a homoclinic or saddle--loop bifurcation, which predicts that the ultrasound is emitted in the form of pulses or spikes with arbitrarily low frequency.Comment: 5 pages, 5 figure

Three-body structure of low-lying 12Be states

We investigate to what extent a description of 12Be as a three-body system made of an inert 10Be-core and two neutrons is able to reproduce the experimental 12Be data. Three-body wave functions are obtained with the hyperspherical adiabatic expansion method. We study the discrete spectrum of 12Be, the structure of the different states, the predominant transition strengths, and the continuum energy spectrum after high energy fragmentation on a light target. Two 0+, one 2+, one 1- and one 0- bound states are found where the first four are known experimentally whereas the 0- is predicted as an isomeric state. An effective neutron charge, reproducing the measured B(E1) transition and the charge rms radius in 11Be, leads to a computed B(E1) transition strength for 12Be in agreement with the experimental value. For the E0 and E2 transitions the contributions from core excitations could be more significant. The experimental 10Be-neutron continuum energy spectrum is also well reproduced except in the energy region corresponding to the 3/2- resonance in 11Be where core excitations contribute.Comment: 16 pages, 9 figures. Accepted for publication in Physical Review

Excitability in a nonlinear magnetoacoustic resonator

We report a nonlinear acoustic system displaying excitability. The considered system is a magnetostrictive material where acoustic waves are parametrically generated. For a set of parameters, the system presents homoclinic and heteroclinic dynamics, whose boundaries define a excitability domain. The excitable behaviour is characterized by analyzing the response of the system to different external stimuli. Single spiking and bursting regimes have been identified.Comment: 4 pages, 5 figure

Thaumetopoea Pinivora Treitschke, 1834, Thaumetopoidae nou per a la fauna de Catalunya (Lepidoptera)

Se da cuenta del hallazgo en Cataluña (Els Coms de Das, Baixa Cerdanya, Pirineo oriental) de Thaumetopoea pinivora Treitschke, 1834, Thaumetopoeidae nuevo para la región. Se exponent los aspectos más interesantes de su bionomía y se pone al día la distribución de esta especie en la Península Ibérica.Thaumetopoea pinivora Treitschke, 1834, Thaumetopoidae new for Catalonia (Lepidoptera). In this paper the authors report the found in Catalonia (Els Coms de Das, Baixa Cerdanya, Pirineu oriental) of Thaumetopoea pinivora Treitschke, 1834, Thaumetopoeidae new for the area. We expose the more interesting aspects of its bionomy and actualize its distribution in the lberian fauna

Functional barriers to the adoption of electronic banking: The moderating effect of gender

The adoption of electronic banking in Spain is lower compared to other countries. This study analyzes the barriers that prevent its adoption, with the conceptual framework of the theory of resistance to innovation. In addition, it analyzes the moderating effect of gender on these barriers. Using structural equations, through PLS and multi-group analysis, the results confirm consumer resistance to electronic banking adoption by functional barriers. It highlights the importance of the value barrier, being this aspect of particular relevance for men, while women are more affected by the complexity in the use of electronic banking. These results have implications for management in overcoming non-adopters’ resistance to the innovation. La adopción de la banca electrónica en España es menor en comparación con otros países. Este estudio analiza las barreras que impiden su adopción, con el marco conceptual de la teoría de la resistencia a la innovación. Además, analiza el efecto moderador del género sobre estas barreras. Utilizando ecuaciones estructurales, a través de PLS y análisis multi-grupo, los resultados confirman la resistencia del consumidor a la adopción de la banca electrónica por barreras funcionales. Destaca la importancia de la barrera de valor, siendo este aspecto de especial relevancia para los hombres, mientras que a las mujeres les impacta más la complejidad en el uso de la banca electrónica. Estos resultados tienen implicaciones para la gestión para superar la resistencia de los no adoptantes a la innovación