Tunable Fano resonance in symmetric multilayered gold nanoshells

Fano resonances (FRs) are produced when a discrete state is coupled with a continuum. In addition to fundamental scientific interests, FRs in plasmonic systems give rise to the so-called plasmon-induced transparency. In this work we have studied the evolution of dipole-dipole all-plasmonic FRs in symmetric multilayered nanoshells as the function of their geometrical parameters. We demonstrate that symmetry breaking is not mandatory for controlling the Fano resonance in such multilayered nanoshells. Generation of FRs in these symmetric nanostructures presents clear advantages over their asymmetric counterparts, as they are easier to fabricate and can be used in a wider range of technological applications

Intervención psicosocial en crianza contemporánea

Las familias y con ellas la crianza, se conciben dinámicas y evolutivas en el tiempo, de ahí la necesidad de intervenciones psicosociales que estén en sintonía con sus necesidades y demandas.  Al respecto, este libro resultado de investigación, no se trata de un manual para los profesionales que atienden el tema, más bien genera un contexto de reflexividad que convoca a la cualificación constante, en atención a la complejidad que reviste el proceso de crianza y la relación con los profesionales que lo apoyan y acompañan. De este modo, se describen entre otros aspectos, algunas estrategias y técnicas que pueden ser útiles para quienes contribuyen al crecimiento integral de las familias, particularmente en el tema de crianza, auspiciando un ambiente de bienestar

Ionoluminescence on α-quartz: mechanisms and modeling

Ionoluminescence of α - quartz exhibits two dominant emission bands peaking at 1.9 eV. (NBOHCs) and 2.7 eV (STEs. The evolution of the red emission yield does not show a correlation with the concentrations of neither the NBOHC nor with that of other color centers. The blue emission yield closely follows the amorphization kinetics independently measured by RBS/C spectrometry. A simple theoretical model has been proposed; it assumes that the formation and recombination of STEs are the primary event and both, the light emissions and the lattice structural damage are a consequence this phenomenon. The model leads to several simple mathematical equations that can be used to simulate the IL yields and provide a reasonable fit to experimental kinetic data

Refractive index changes in amorphous SiO2 (silica) by swift ion irradiation

The refractive index changes induced by swift ion-beam irradiation in silica have been measured either by spectroscopic ellipsometry or through the effective indices of the optical modes propagating through the irradiated structure. The optical response has been analyzed by considering an effective homogeneous medium to simulate the nanostructured irradiated system consisting of cylindrical tracks, associated to the ion impacts, embedded into a virgin material. The role of both, irradiation fluence and stopping power, has been investigated. Above a certain electronic stopping power threshold (∼2.5 keV/nm), every ion impact creates an axial region around the trajectory with a fixed refractive index (around n = 1.475) corresponding to a certain structural phase that is independent of stopping power. The results have been compared with previous data measured by means of infrared spectroscopy and small-angle X-ray scattering; possible mechanisms and theoretical models are discussed

Comparative study of ion beam-irradiation effects on silica and α-quartz: evidences for excitonic mechanisms

Introduction - SiO 2 •Simple composition and structure; Crystalline and amorphous phases •Adequate for atomistic simulations •Abundant in nature. Relevant for many technologies -Irradiation with swift heavy ions: •They provide EXTREME physical conditions •Very high excitation densities similar to high power lasers •Very high local temperatures •By playing with high energy and heavy mass (SHI) : •One can go from low electronic excitations (collisions regime) to high electronic excitations (electronic regim

Kinetics of amorphization induced by swift heavy ions in α-quartz

The kinetics of amorphization in crystalline SiO2 (α-quartz) under irradiation with swift heavy ions (O+1 at 4 MeV, O+4 at 13 MeV, F+2 at 5 MeV, F+4 at 15 MeV, Cl+3 at 10 MeV, Cl+4 at 20 MeV, Br+5 at 15 and 25 MeV and Br+8 at 40 MeV) has been analyzed in this work with an Avrami-type law and also with a recently developed cumulative approach (track-overlap model). This latter model assumes a track morphology consisting of an amorphous core (area σ) and a surrounding defective halo (area h), both being axially symmetric. The parameters of the two approaches which provide the best fit to the experimental data have been obtained as a function of the electronic stopping power Se. The extrapolation of the σ(Se) dependence yields a threshold value for amorphization, Sth ≈ 2.1 keV/nm; a second threshold is also observed around 4.1 keV/nm. We believe that this double-threshold effect could be related to the appearance of discontinuous tracks in the region between 2.1 and 4.1 keV/nm. For stopping power values around or below the lower threshold, where the ratio h/σ is large, the track-overlap model provides a much better fit than the Avrami function. Therefore, the data show that a right modeling of the amorphization kinetics needs to take into account the contribution of the defective track halo. Finally, a short comparative discussion with the kinetic laws obtained for elastic collision damage is given

Ionoluminescence induced by swift heavy ions in silica and quartz: A comparative analysis

Ionoluminescence (IL) of the two SiO 2 phases, amorphous silica and crystalline quartz, has been comparatively investigated in this work, in order to learn about the structural defects generated by means of ion irradiation and the role of crystalline order on the damage processes. Irradiations have been performed with Cl at 10 MeV and Br at 15 MeV, corresponding to the electronic stopping regime (i.e., where the electronic stopping power S e is dominant) and well above the amorphization threshold. The light-emission kinetics for the two main emission bands, located at 1.9 eV (652 nm) and 2.7 eV (459 nm), has been measured under the same ion irradiation conditions as a function of fluence for both, silica and quartz. The role of electronic stopping power has been also investigated and discussed within current views for electronic damage. Our experiments provide a rich phenomenological background that should help to elucidate the mechanisms responsible for light emission and defect creationThis work has been supported by Spanish Ministry MICINN through the project MAT-2008-06794-C03-03, JCI-2009-05681, and by Madrid Community through the project TECHNOFUSION (S2009/ENE-1679). OPR is grateful to CONACyT, Mexico, for extending a postdoctoral fellowshi

Crianza contemporánea: Significados y comprensiones desde la voz de las familias

Este libro resultado de un proceso de investigación, vincula aspectos teóricos y metodológicos en la intervención de familias en el tema de crianza; con respecto al componente práctico, incluye estrategias y técnicas que pueden ser adoptadas por los profesionales del área psicosocial, especialmente psicólogos, trabajadores sociales, profesionales en desarrollo familiar y terapeutas familiares.    El texto incluye, además, un análisis de los motivos de consulta que describen los padres de familia en el tema de crianza, en el contexto de un proceso de intervención profesional o institucional, y con ellos los desafíos para lograr su comprensión y análisis, direccionados al bienestar de las familias intervenidas. Finalmente, los resultados de la investigación colocan en reflexión las técnicas y estrategias que utilizan los profesionales psicosociales en el tema de crianza; en correspondencia con sus fundamentos teóricos y metodológicos, mediatizados por aspectos éticos

Formas de intervención psicosocial para familias que consultan por temas de crianza

El artículo resalta el interés por identificar las formas de intervención de los profesionales psicosociales que trabajan actualmente con familias consultantes en el tema de crianza. Para ello, se hizo un acercamiento a 16 profesionales expertos en este tipo de abordajes. En este sentido, se tuvo por objeto conocer las formas, estrategias y técnicas adoptadas por profesionales en el proceso de intervención en crianza, así como también los motivos de consulta que llevan a los padres a solicitar apoyo profesional. El enfoque del estudio es cualitativo, al favorecer aspectos descriptivos e interpretativos acordes a los objetivos propuestos, con apropiación del análisis de contenido (AC) como metodología de trabajo. Los resultados colocan en reflexión y análisis las técnicas y estrategias que utilizan los profesionales en sus intervenciones en el tema de crianza; en correspondencia a su fundamentación teórica y metodológica

Ionoluminescence induced by swift heavy ions in silica and quartz: a comparative analysis

Ionoluminescence (IL) of the two SiO2 phases, amorphous silica and crystalline quartz, has been comparatively investigated in this work, in order to learn about the structural defects generated by means of ion irradiation and the role of crystalline order on the damage processes. Irradiations have been performed with Cl at 10 MeV and Br at 15 MeV, corresponding to the electronic stopping regime (i.e., where the electronic stopping power Se is dominant) and well above the amorphization threshold. The light-emission kinetics for the two main emission bands, located at 1.9 eV (652 nm) and 2.7 eV (459 nm), has been measured under the same ion irradiation conditions as a function of fluence for both, silica and quartz. The role of electronic stopping power has been also investigated and discussed within current views for electronic damage. Our experiments provide a rich phenomenological background that should help to elucidate the mechanisms responsible for light emission and defect creation