Electropolymerisation of 3,4-ethylenedioxythiophene in aqueous solutions

The potentiostatic electrosynthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) in aqueous media without addition to the solution of any kind of surfactant has been studied by electrochemical quartz crystal microbalance (EQCM) and by spectroelectrochemistry. These tandem techniques have given valuable new information about the electropolymerisation process, allowing us to relate absorbance-charge and frequency-charge relationships to: (i) oligomers generation and chain propagation, as far as the length leading to precipitation is reached; (ii) growing of the polymer deposit and concomitant p-doping, and even (iii) overoxidation of the polymer film. An analysis of the whole of the data, in fact, shows that the charge spent is not necessarily totally involved in thepolymer deposit formation, growth, and p-doping, so that it is necessary to be particularly careful in the fitting of the experimental data to linear models

HH 223: a parsec-scale H2 outflow in the star-forming region L723

The dark cloud Lynds 723 (L723) is a low-mass star-forming region where one of the few known cases of a quadrupolar CO outflow has been reported. Two recent works have found that the radio continuum source VLA 2, towards the centre of the CO outflow, is actually a multiple system of young stellar objects (YSOs). Several line-emission nebulae that lie projected on the east-west CO outflow were detected in narrow-band Halpha and [SII] images. The spectra of the knots are characteristic of shock-excited gas (Herbig-Haro spectra), with supersonic blueshifted velocities, which suggests an optical outflow also powered by the VLA 2 YSO system of L723. We imaged a field of ~5' X 5' centred on HH 223, which includes the whole region of the quadrupolar CO outflow with nir narrow-band filters . The H2 line-emission structures appear distributed over a region of 5.5' (0.5 pc for a distance of 300 pc) at both sides of the VLA 2 YSO system, with an S-shape morphology, and are projected onto the east-west CO outflow. Most of them were resolved in smaller knotty substructures. The [FeII] emission only appears associated with HH 223. An additional nebular emission from the continuum in Hc and Kc appears associated with HH 223-K1, the structure closest to the VLA 2 YSO system, and could be tracing the cavity walls. We propose that the H2 structures form part of a large-scale near-infrared outflow, which is also associated with the VLA 2 YSO system. The current data do not allow us to discern which of the YSOs of VLA 2 is powering this large scale optical/near-infrared outflow.Comment: Accepted for A&A http://dx.doi.org/10.1051/0004-6361/201015125 12 pages, 9 figure

Influence of vulnerability factors in panic disorder severity

Background: We studied herein the predictive value for panic severity of three well-based vulnerability factors: personality traits (neuroticism and extraversion; NEO-PI-R), anxiety sensitivity (ASI), and perceived control (ACQ-R). Method: The sample was composed of 52 participants diagnosed with panic disorder, with or without agoraphobia, according to DSM-IV-TR criteria. Results: Our results revealed that the anxiety facet is a better predictor of panic severity than neuroticism. Anxiety sensitivity increases the predictive value for panic severity and, finally, perception of control of emotions is the only perception control subscale that increases the predictive value for panic severity more than the anxiety facet and anxiety sensitivity. Conclusions: This finding supports the assumption of the importance of taking into account the assessment of the lower order dimensions of the vulnerability factors in the field of psychopathology studies. Furthermore, the predictive value of perception of control of emotions indicates the importance of this specific vulnerability factor in the etiology of panic disorder (with or without agoraphobia) and, thus, shows the necessity to include emotion regulation strategies in the psychological treatments

The management of lifeguards in natural acuatic spaces (beaches)

Este estudio nace con la necesidad de establecer criterios básicos y descripción de recomendaciones para mejorar el nivel de atención de los socorristas acuáticos profesionales en los espacios acuáticos naturales, concretamente en el trabajo realizado en las playas, con el objetivo de aumentar la seguridad de estas zonas de baño. El estudio se ha desarrollado en la Comunidad Autónoma de Cataluña, concretamente en tres playas de varios municipios de la provincia de Barcelona. Se puede afirmar que tras esta investigación la mayor parte de los socorristas acuáticos que han participado en el estudio valoraron positivamente las medidas y criterios propuestos, asumiendo que con los mismos se puede desempeñar mejor su trabajoThis study arises from the need to establish basic criteria and the description of recommendations to improve the level of responsiveness of lifeguards in natural aquatic areas, specifically in the work done on the beaches, in order to increase the safety of these bathing areas. The study was developed Cataluña, in three beaches of different municipalities in the province of Barcelona. We can aver after this research that most of the lifeguards who participated in the study value positively the proposed measures and criteria, through the assumption that these features help improve their wor

Optimal light harvesting structures at optical and infrared frequencies

One-dimensional light harvesting structures with a realistic geometry nano-patterned on an opaque metallic film are optimized to render high transmission efficiencies at optical and infrared frequencies. Simple design rules are developed for the particular case of a slit-groove array with a given number of grooves that are symmetrically distributed with respect to a central slit. These rules take advantage of the hybridization of Fabry-Perot modes in the slit and surface modes of the corrugated metal surface. Same design rules apply for optical and infrared frequencies. The parameter space of the groove array is also examined with a conjugate gradient optimization algorithm that used as a seed the geometries optimized following physical intuition. Both uniform and nonuniform groove arrays are considered. The largest transmission enhancement, with respect to a uniform array, is obtained for a chirped groove profile. Such enhancement is a function of the wavelength. It decreases from 39% in the optical part of the spectrum to 15% at the long wavelength infrared.Comment: 13 pages, 5 figure

Nonlinear response of single-molecule nanomagnets: equilibrium and dynamical

We present an experimental study of the {\em nonlinear} susceptibility of Mn$_{12}$ single-molecule magnets. We investigate both their thermal-equilibrium and dynamical nonlinear responses. The equilibrium results show the sensitivity of the nonlinear susceptibility to the magnetic anisotropy, which is nearly absent in the linear response for axes distributed at random. The nonlinear dynamic response of Mn$_{12}$ was recently found to be very large and displaying peaks reversed with respect to classical superparamagnets [F. Luis {\em et al.}, Phys. Rev. Lett. {\bf 92}, 107201 (2004)]. Here we corroborate the proposed explanation -- strong field dependence of the relaxation rate due to the detuning of tunnel energy levels. This is done by studying the orientational dependence of the nonlinear susceptibility, which permits to isolate the quantum detuning contribution. Besides, from the analysis of the longitudinal and transverse contributions we estimate a bound for the decoherence time due to the coupling to the phonon bath.Comment: 13 pages, 8 figures, resubmitted to Phys. Rev. B with minor change