Femtosecond real-time probing of reactions. IX. Hydrogen-atom transfer

The real-time dynamics of hydrogen-atom-transfer processes under collisionless conditions are studied using femtosecond depletion techniques. The experiments focus on the methyl salicylate system, which exhibits ultrafast hydrogen motion between two oxygen atoms due to molecular tautomerization, loosely referred to as intramolecular ''proton'' transfer. To test for tunneling and mass effects on the excited potential surface, we also studied deuterium and methyl-group substitutions. We observe that the motion of the hydrogen, under collisionless conditions, takes place within 60 fs. At longer times, on the picosecond time scale, the hydrogen-transferred form decays with a threshold of 15.5 kJ/mol; this decay behavior was observed up to a total vibrational energy of approximately 7200 cm-1. The observed dynamics provide the global nature of the motion, which takes into account bonding before and after the motion, and the evolution of the wave packet from the initial nonequilibrium state to the transferred form along the O-H-O reaction coordinate. The vibrational periods (2pi/omega) of the relevant modes range from 13 fs (the OH stretch) to 190 fs (the low-frequency distortion) and the motion involves (in part) these coordinates. The intramolecular vibrational-energy redistribution dynamics at longer times are important to the hydrogen-bond dissociation and to the nonradiative decay of the hydrogen-transferred form

Gymnopus Beltraniae, a new species of section Vestipedes (Agaricales) from the Canary Islands (Spain)

Gymnopus beltraniae, collected on the Canary Islands in 'monteverde'forest as well as mixed monteverde /Canary pine forest, is proposed as a new species belonging to sect. Vestipedes subsect. Vestipedes. It is compared with species from North and South America considered to represent the closest taxa in its section

Gymnopus Beltraniae, a new species of section Vestipedes (Agaricales) from the Canary Islands (Spain)

Gymnopus beltraniae, collected on the Canary Islands in 'monteverde'forest as well as mixed monteverde /Canary pine forest, is proposed as a new species belonging to sect. Vestipedes subsect. Vestipedes. It is compared with species from North and South America considered to represent the closest taxa in its section

Insights into the room temperature magnetism of ZnO/Co3O4 mixtures

The origin of room temperature (RT) ferromagneticlike behavior in ZnO-based diluted magnetic semiconductors is still an unclear topic. The present work concentrates on the appearance of RT magnetic moments in just mixed ZnO/Co3O4 mixtures without thermal treatment. In this study, it is shown that the magnetism seems to be related to surface reduction of the Co3O4 nanoparticles, in which, an antiferromagnetic Co3O4 nanoparticle (core) is surrounded by a CoO-like shell. This singular superficial magnetism has also been found in other mixtures with semiconductors such as TiO2 and insulators such as Al2O3

Organización Docente de la Asignatura Ingeniería de los Sistemas Basados en el Conocimiento

En este trabajo se presentan los objetivos, los contenidos y los métodos de enseñanza de la asignatura de Ingeniería de los Sistemas Basados en el Conocimiento (ISBC). La asignatura es una optativa que complementa las asignaturas troncales de Inteligencia Artificial e Ingeniería del Conocimiento. En la asignatura se hace especial hincapié en los temas de representación del conocimiento y en el empleo de entornos que integran distintos lenguajes de representación. El enfoque de la asignatura es eminentemente práctico, planteándose las clases teóricas alrededor de ejemplos de diseño e implementación para la presentación de los conceptos. En cuanto a los trabajos de la asignatura, además de las prácticas, se ha dado opción a la participación en proyectos en los que se ven las aplicaciones de la ISBC como un valor añadido

Aspectos docentes de la asignatura de “Inteligencia Artificial e Ingeniería del Conocimiento 1” del plan de estudios de Ingeniería Informática de la Universidad de Zaragoza

En este trabajo se presentan los aspectos docentes de la asignatura de Inteligencia Artificial e Ingeniería del Conocimiento 1. Es una asignatura restringida a la parte de introducción, búsqueda y representación del conocimiento y con un especial hincapié en la programación, generalmente con Common Lisp

An ab initio study of the photodissociation of CH2I and CH2I+

8 pags., 5 figs., 4 tabs.Photodissociation of the CH2I radical and the CH2I+ cation is studied by means of high-level ab initio calculations, including spin-orbit effects. Potential-energy curves (PEC) along the dissociating bond distances involved in some fragmentation pathways of these species are computed for the ground and several excited electronic states. Based on the PECs obtained, the possible photodissociation mechanisms are analyzed and suggested. Significant differences are found between the fragmentation dynamics of the neutral radical and that of the cation. While a relatively simple dissociation dynamics is predicted for CH2I, more complex fragmentation mechanisms involving internal conversion and couplings between different excited electronic states are expected for CH2I+. The species studied here are relevant to atmospheric chemistry, and the present work can help to understand better how their photodissociation may affect chemical processes in the atmosphere.This work was funded by the Ministerio de Ciencia e Innovación (MICINN, Spain), grant no. PGC2018-096444-B-I00, PID2019-107115GB-C21, PID2021-122549NB-C21, PID2021-122796NB-I00, and PID2021- 122839NB-I00. A. B. acknowledges funding from the I-COOP program from CSIC, grant no. COOPB20364, which made possible a research stay at Instituto de Fısica Fundamental, CSIC. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkłodowskaCurie grant agreement no. 872081, and from the COST Action CA21101 (COSY). The Centro de Supercomputacion de Galicia (CESGA, Spain) is acknowledged for the use of its resources.Peer reviewe

Cultivation of Gongolaria barbata (Fucales, Phaeophyceae) with a seaweed-derived biostimulant in order to improve photophysiological fitness and promote fertility to advance the restoration of marine macroalgal forests

As a result of several anthropogenic factors, Cystoseira sensu lato forests have declined or become regionally extinct in many coastal regions of the Mediterranean. Given the low natural recovery of lost populations, research efforts have been encouraged to develop sustainable and efficient restoration of macroalgal forests on a large scale. By promoting growth and fertility of collected thallus branches under controlled laboratory conditions, the availability of seedlings for restoration could be ensured without jeopardizing natural populations. Here we investigated the effect of a commercial algal biostimulant (AlgatronCifo (R)) on the photophysiology, growth and fertility of Gongolaria barbata (Stackhouse) Kuntze (Fucales, Phaeophyceae). In a factorial laboratory experiment, two different temperatures (10 oC and 14 degrees C) and two culture media [i.e. seawater (SW) and Algatron (AT)] were tested. The photosynthetic performance of G. barbata doubled after three weeks of culture with AT, while it decreased by 25% when cultivated in SW. The highest photosynthetic performance and growth were achieved at 14oC with AT, where fertile receptacles also developed, followed by seedling settlements. The thalli cultured in AT had similar or better photosynthetic performance than the initial control thalli. AT-cultured thalli had a greater ability to quench energy via photochemical pathways (q(P)) than those from the SW, which on the contrary, had higher levels of non-photochemical responses (q(N), NPQ(max)). This limited photosynthetic performance was probably linked to the higher P-limitation experienced under that treatment. The algal biostimulant enhanced the physiological performance and induced fertility of G. barbata, demonstrating its valorization potential and setting a new path for improved restoration applications