A search for hydrogenated fullerenes in fullerene-containing planetary nebulae

Detections of C60 and C70 fullerenes in planetary nebulae (PNe) of the Magellanic Clouds and of our own Galaxy have raised the idea that other forms of carbon such as hydrogenated fullerenes (fulleranes like C60H36 and C60H18), buckyonions, and carbon nanotubes, may be widespread in the Universe. Here we present VLT/ISAAC spectra (R ~600) in the 2.9-4.1 microns spectral region for the Galactic PNe Tc 1 and M 1-20, which have been used to search for fullerene-based molecules in their fullerene-rich circumstellar environments. We report the non-detection of the most intense infrared bands of several fulleranes around ~3.4-3.6 microns in both PNe. We conclude that if fulleranes are present in the fullerene-containing circumstellar environments of these PNe, then they seem to be by far less abundant than C60 and C70. Our non-detections together with the (tentative) fulleranes detection in the proto-PN IRAS 01005+7910 suggest that fulleranes may be formed in the short transition phase between AGB stars and PNe but they are quickly destroyed by the UV radiation field from the central star.Comment: Accepted for publication in Astronomy & Astrophysics (7 pages, 3 figures, and 3 Tables

Large quantum nonlinear dynamic susceptibility of single-molecule magnets

The nonlinear dynamical response of Mn$_{12}$ single-molecule magnets is experimentally found to be very large, quite insensitive to the spin-lattice coupling constant, and displaying peaks reversed with respect to classical superparamagnets. It is shown that these features are caused by the strong field dependence of the relaxation rate due to the detuning of energy levels between which tunneling takes place. The nonlinear susceptibility technique, previously overlooked, is thus proposed as a privileged probe to ascertain the occurrence of quantum effects in mesoscopic magnetic systems.Comment: 4 pages, 4 figure

The response of taxonomic and functional diversity of the seed bank to agricultural intensification and soil properties in two Mediterranean cereal areas

Weed seed bank diversity has been severely impacted by agriculture intensifi cation. However, the functional consequences have been poorly studied in highly intensifi ed agro-ecosystems.Postprint (published version

What is the evidence based public health?

Evidence based Public Health is the execution and evaluation of the efficiency of interventions, plans, programs, projects and politics in public health through the application of the scientific principles of reasoning, including the systematic use of information and information systems. Evidence based public health involves the use of methodologies similar to those applied in evidence-based clinical medicine, but differs in its contents. In public health two types of evidence are described. The type I evidence in which a strong relation exists between the preventable risk and disease, and type II evidence in which there exists a relative effectivity of the public health interventions. In evidence based Public Health research designs more appropriate for the social sciences are used, as the observational and quasi-experimental studies. Likewise the decisions are more of interdisciplinary teams.La Salud Pública Basada en la Evidencia es la ejecución y la evaluación de la efectividad de intervenciones, planes, programas, proyectos y políticas en salud pública a través de la aplicación de los principios de razonamiento científicos, incluyendo el uso sistemático de datos y sistemas de información. La evidencia en salud pública implica la utilización de metodologías similares a las aplicadas en la evidencia en medicina clínica pero que difieren en sus contenidos, es así que en salud pública se describen dos tipos de evidencia. La evidencia tipo I en la cual existe una fuerte relación entre el riesgo prevenible y la enfermedad y la tipo II en la que existe una efectividad relativa de las intervenciones en salud pública. En Salud Pública Basada en la Evidencia se utilizan diseños de investigación más propios de las ciencias sociales como son los estudios observacionales y cuasi-experimentales. Así mismo las decisiones son más de equipos interdisciplinarios

Paleo and historical seismicity in Mallorca (Baleares, Spain): a preliminary approach

The island of Mallorca is subject to low seismic activity. The instrumental record shows that current seismicity is surficial (La isla de Mallorca presenta una actividad sísmica baja. El registro instrumental muestra que la sismicidad actual es superficial

Ajustes de un algoritmo híbrido basado en SA aplicado al diseño óptimo de redes de sensores

Sensor network design problem (SNDP) in process plants includes the determination of which process variables should be measured to achieve a required degree of knowledge about the plant. We propose to solve the SNDP problem in plants of increasing size and complexity using a hybrid algorithm based on Simulated Annealing (HSA) as main metaheuristic and Tabu Search embedded with Strategic Oscillation (SOTS) as a subordinate metaheuristic. We studied the tuning of control parameters in order to improve the HSA performance. Experimental results indicate that a high-quality solution in reasonable computational times can be found by HSA effectively. Moreover, HSA shows good features solving SNDP compared with proposals from the literature.Facultad de Informátic

Optimal Instrumentation: Adjustment and Hybridization of a Simulated Annealing Based Technique

This work presents an analysis on the behavior of a particular metaheuristic technique inspired by Simulated Annealing, SA, for the resolution of a problem of sensor network design in process plants, SNDP. This design problem is formulated as a combinatorial optimization problem and includes the selection and determination of the number of process variables that must be measured to achieve the specific state of knowledge about the plant. Different parametric configurations for the proposed heuristic are analyzed and discussed, as well as their performance in plants of increasing size and complexity.XX Workshop Agentes y Sistemas Inteligentes.Red de Universidades con Carreras en Informátic