The 3s Rydberg state as a doorway state in the ultrafast dynamics of 1,1-difluoroethylene

The deactivation dynamics of 1,1-difluoroethylene after light excitation is studied within the surface hopping formalism in the presence of 3s and 3p Rydberg states using multi-state second order perturbation theory (MS-CASPT2). Due to the proximity of the Rydberg π-3s state with the ππ* state, the states are mixed favoring ultrafast exchange of population via a conical intersection that closely resembles the equilibrium structure. After excitation, it is found that the π-3s state acts as a doorway state, trapping the population and delaying internal conversion to the ππ* state, from which deactivation to the closed-shell ground state takes place. Besides the conical intersection between the π-3s and ππ* states, five additional conical intersections between the ππ* state and the ground state are found, indicating that after the system is excited, it stretches the C[double bond, length as m-dash]C bond before it twists and pyramidalizes at any of the carbon atoms, in the spirit of a hula-twist mechanism

Papiloma de plexo coroideo del cuarto ventrículo cerebral : diagnóstico y tratamiento quirúrgico

Se trata de una perra mestiza, de ocho años de edad y unos 30 kg de peso, con hemiparesis e inclinación de la cabeza hacia el lado izquierdo. Tras realizar una resonancia magnética nuclear (RMN) se identificó la lesión, compatible con una neoplasia, en fosa posterior a nivel del cuarto ventrículo cerebral. El tratamiento quirúrgico consistió en una craneotomía suboccipital que permitió el acceso a la fosa posterior, para poder así extraer el tumor. El resultado obtenido tras la cirugía se puede considerar satisfactorio, si tenemos en cuenta el alto grado de morbilidad que supone trabajar en esta regiónHerein, we report the case of an eight-year-old, 30 kg, female mixed-breed dog, with hemiparesis and left head tilt. Magnetic resonance imaging led to identify the lession as a tumor in the caudal fossa of the fourth ventricle. The surgical treatment consisted of a suboccipital craniotomy, which allowed the access to the caudal fossa, and the xtirpation of the tumor. A satisfactory result was achieved after the surgery, if we consider the high sick rate involved when working in this region

Metallo-Dielectric Colloidal Films as SERS Substrate

Along this chapter, we probe that the discrete dipole approximation models fairly well the optical response of periodic systems. Herein, we use it to model the reflectance and transmittance, at normal incidence, of colloidal films made of SiO2 spheres. As the thickness increases from 1 to 12 layers, the photonic band gap shifts to the blue tending to the value corresponding to a 3D opal, 442 nm. A film with more than eight layers resembles the bulk properties of a 3D opal. Our results are compared to a real sample. Besides, we show that taking advantage of the wide and asymmetrical absorbance spectrum of an opal with Au NPs is possible to identify the contribution of each component in the overall spectrum, through a deconvolution analysis. Finally, we present the electric field intensity as the content of metal NP increases in a monolayer. We consider NPs one order of magnitude smaller than the silica spheres, and then, 6, 9, and 17 NPs are hosted in the void. Similar average electric field intensities, about 11 times the incident intensity, are obtained with Au and Ag NPs. But, the spots with these intensities cover a bigger area with Ag NPs than with Au NPs

A conjecture on Exceptional Orthogonal Polynomials

Exceptional orthogonal polynomial systems (X-OPS) arise as eigenfunctions of Sturm-Liouville problems and generalize in this sense the classical families of Hermite, Laguerre and Jacobi. They also generalize the family of CPRS orthogonal polynomials. We formulate the following conjecture: every exceptional orthogonal polynomial system is related to a classical system by a Darboux-Crum transformation. We give a proof of this conjecture for codimension 2 exceptional orthogonal polynomials (X2-OPs). As a by-product of this analysis, we prove a Bochner-type theorem classifying all possible X2-OPS. The classification includes all cases known to date plus some new examples of X2-Laguerre and X2-Jacobi polynomials

Uprolides N, O and P from the Panamanian Octocoral Eunicea succinea.

Three new diterpenes, uprolide N (1), uprolide O (2), uprolide P (3) and a known one, dolabellane (4), were isolated from the CH₂Cl₂-MeOH extract of the gorgonian octocoral Eunicea succinea, collected from Bocas del Toro, on the Caribbean coast of Panama. Their structures were determined using spectroscopic analyses, including 1D and 2D NMR and high-resolution mass spectrometry (HRMS) together with molecular modeling studies. Compounds 1-3 displayed anti-inflammatory properties by inhibiting production of Tumor Necrosis Factor (TNF) and Interleukin (IL)-6 induced by lipopolysaccharide (LPS) in murine macrophages

Using synchronization to improve earthquake forecasting in a cellular automaton model

A new forecasting strategy for stochastic systems is introduced. It is inspired by the concept of anticipated synchronization between pairs of chaotic oscillators, recently developed in the area of Dynamical Systems, and by the earthquake forecasting algorithms in which different pattern recognition functions are used for identifying seismic premonitory phenomena. In the new strategy, copies (clones) of the original system (the master) are defined, and they are driven using rules that tend to synchronize them with the master dynamics. The observation of definite patterns in the state of the clones is the signal for connecting an alarm in the original system that efficiently marks the impending occurrence of a catastrophic event. The power of this method is quantitatively illustrated by forecasting the occurrence of characteristic earthquakes in the so-called Minimalist Model.Comment: 4 pages, 3 figure

Influence of the molecular interaction in the value of molecular volume for the isotropicnematic transition of p-azoxianisol using th emodel HERSW in conjuntion with IPCM model

In this work, we analyzed the experimental pressure-temperature behavior in the Isotropic-Nematic phase transitionfor the liquid crystal p-azoxianisol at 1 atm using a development for the HERSW Conveg Peg model. Additionally, we obtained the values of the molecular volumes for the hard and attractive cores from theoretical quantum calculations at PM3, PM6 and B3LYP/6-311++G levels considering the molecular interaction among the liquidcrystals (PAA)5. We found that the best prediction for experimental data appears when the effect of the molecular interaction is considered in the volume calculation. Specifically for a/b=3.7, V0=70.86 A3 and a/bl=1.95 the best prediction was obtained