Surface structuring of fused silica with asymmetric femtosecond laser pulse bursts

Fused silica surface structuring has been performed using temporally shaped femtosecond laser pulses. For this purpose we have designed pulse bursts with a triangular intensity envelope and different slope sign and interpulse separation that were experimentally generated using a home-made temporal pulse shaper. We have found that pulse bursts with decreasing intensity envelopes are remarkably more efficient in terms of surface ablation than bursts with increasing intensity envelopes. The results reveal that laser energy coupling in the material is enhanced as the interpulse spacing decreases. A study of the ablation depth using stretched single pulses was carried out and compared to results obtained for pulse bursts with different interpulse spacing. We find that the deepest crater was achieved with bursts of 0.5 ps interpulse separation and decreasing envelope. This pulse form also induced the largest change of the surface reflectivity after irradiation. The results are discussed in terms of how the laser energy coupling efficiency is linked to the temporal pulse shape. © 2013 Optical Society of America.This work has been partially supported by the Spanish TEC2011-22422 project. J. H.-R. acknowledges a grant awarded by the Spanish Ministry of Science and Innovation.Peer Reviewe

Gamma-ray and neutrino fluxes from Heavy Dark Matter in the Galactic Center

We present a study of the Galactic Center region as a possible source of both secondary gamma-ray and neutrino fluxes from annihilating dark matter. We have studied the gamma-ray flux observed by the High Energy Stereoscopic System (HESS) from the J1745-290 Galactic Center source. The data are well fitted as annihilating dark matter in combination with an astrophysical background. The analysis was performed by means of simulated gamma spectra produced by Monte Carlo event generators packages. We analyze the differences in the spectra obtained by the various Monte Carlo codes developed so far in particle physics. We show that, within some uncertainty, the HESS data can be fitted as a signal from a heavy dark matter density distribution peaked at the Galactic Center, with a power-law for the background with a spectral index which is compatible with the Fermi-Large Area Telescope (LAT) data from the same region. If this kind of dark matter distribution generates the gamma-ray flux observed by HESS, we also expect to observe a neutrino flux. We show prospective results for the observation of secondary neutrinos with the Astronomy with a Neutrino Telescope and Abyss environmental RESearch project (ANTARES), Ice Cube Neutrino Observatory (Ice Cube) and the Cubic Kilometer Neutrino Telescope (KM3NeT). Prospects solely depend on the device resolution angle when its effective area and the minimum energy threshold are fixed

Independent control of beam astigmatism and ellipticity using a SLM for fs-laser waveguide writing

We have used a low repetition rate (1 kHz), femtosecond laser amplifier in combination with a spatial light modulator (SLM) to write optical waveguides with controllable cross-section inside a phosphate glass sample. The SLM is used to induce a controllable amount of astigmatism in the beam wavefront while the beam ellipticity is controlled through the propagation distance from the SLM to the focusing optics of the writing setup. The beam astigmatism leads to the formation of two separate diskshaped foci lying in orthogonal planes. Additionally, the ellipticity has the effect of enabling control over the relative peak irradiances of the two foci, making it possible to bring the peak irradiance of one of them below the material transformation threshold. This allows producing a single waveguide with controllable cross-section. Numerical simulations of the irradiance distribution at the focal region under different beam shaping conditions are compared to in situ obtained experimental plasma emission images and structures produced inside the glass, leading to a very satisfactory agreement. Finally, guiding structures with controllable crosssection are successfully produced in the phosphate glass using this approach. © 2009 Optical Society of America.This work was partially supported by the Spanish Ministry of Science and Innovation under TEC2008-01183 project. A. R. and W. G. acknowledge their I3P-CSIC postdoctoral con- tracts (co-funded by the European Social Fund). D. P. and A. F. acknowledge their grants under Projects TEC 2005-00074 and TEC 2006-04538.Peer Reviewe

In situ assessment and minimization of nonlinear propagation effects for femtosecond-laser waveguide writing in dielectrics

The effect of nonlinear propagation on the shape of the focal volume has been assessed by in situ plasma emission imaging during the subsurface processing of a commercial phosphate glass. The sample was processed with an elliptically shaped femtosecond-laser beam at 1 kHz repetition rate and scanned transversely with respect to the writing beam axis. As a consequence, optimal conditions for minimizing undesirable nonlinear propagation effects during the production of optical waveguides by direct laser writing have been determined. Under these conditions, it is possible to induce structural transformations and still preserve the focal volume shape associated with the linear propagation regime. While at low pulse energy a single scan laser-written structure does not support a guided mode, the use of multiple scans with minimized nonlinear propagation effects enables the production of optical waveguides. The latter show a significantly improved performance in terms of the refractive index change and propagation losses when compared to single scan waveguides. © 2010 Optical Society of America.This work was partially supported by the University of Zaragoza under Project 223/88 and by the Spanish Ministry of Science and Innovation under TEC2008-01183 project. A. Ruiz de la Cruz and W. Gawelda acknowledge their I3P-CSIC postdoctoral contracts (co-funded by the European Social Fund). D. Puerto and A. Ferrer acknowledge their grants under Projects TEC 2005-00074 and TEC 2006-04538.Peer Reviewe

Considerations on Field Methodology for Macrofungi Studies in Fragmented Forests of Mediterranean Agricultural Landscapes

The methodology used for the determination of macrofungal diversity in Mediterranean areas differs in the time of sampling and the number of years displayed, making it difficult to compare results. Furthermore, the results could be refuted because the studies are being conducted over an insufficient number of years or without considering the variation of the meteorological conditions from one year to the next and its effects on fruiting time, which might not fit the sampling. In order to optimize field work on fungal fruiting in Mediterranean environments dominated by holm oak (Quercus ilex L.), a weekly field analysis of macrofungal diversity from February 2009 to June 2013 was carried out in a Mediterranean holm oak forest in the middle-west of the Iberian Peninsula. The results revealed that fruiting bodies appeared throughout the year and that there was a delay in autumn fruiting, overlapping with spring. All this seems to indicate that weekly collection throughout the year and for a period of two years could be sufficient to estimate the macrofungal biodiversity of this ecosystem. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Compression system for the phonocardiographic signal

An FPGA-based approach is proposed for implementing a compression system developed specifically for the signal of phonocardiogram. The compression method offers better rate and distorsion than standard audio compression techniques. Both the algorithm and the details on the solutions adopted for its implementation are presented in this paper.This work has been supported by Ministerio de Ciencia y Tecnología of Spain, under grant TIN2006-15460-C04-04

Formación universitaria en protección radiológica: nuestra experiencia en la Universidad de Málaga (España)

La Universidad de Málaga (UMA) desde 2011 tiene acreditada la formación en protección radiológica, con homologación del Consejo de Seguridad Nuclear (CSN). Desde este año, hasta nuestros días se han impartido un total de 31 cursos. La temática de los cursos impartidos han sido: director y operador de instalaciones de radiodiagnóstico médico; supervisor y operador de instalaciones radiactivas (radioterapia, medicina nuclear, laboratorio de fuentes no encapsuladas, control de procesos y técnicas analíticas), y de isótopos en el medio marino. Se han formado un total de 397 alumnos, con un 93 % de aprobados, profesionales de la enfermería, médicos, podólogos, veterinarios, odontólogos y auxiliares de higiene bucodental. Los cursos de formación constan de una parte teórica impartida por profesores del departamento de radiología y medicina física, del laboratorio de protección radiológica del CIMES y del servicio de instalación radiactiva; y de otra práctica, desarrollada en los laboratorios IRUMA de los Servicios Centrales de Investigación de la UMA, y en centros asistenciales de Radiología y Radioterapia del grupo VITHAS Salud. Todos estos cursos están integrados en titulaciones propias de la UMA, formando parte de su campus virtual (https://epropias.cv.uma.es/), basado en una plataforma Moodle. Esto supone un total de 159 créditos ECTS impartidos, en cursos de formación superior y de extensión universitaria. Por lo tanto, obtienen una doble titulación integrada

Estimación de niveles de referencia de dosis y contribución a la dosis poblacional de las TC en España

La Tomografía Computarizada (TC) es una de las pruebas de radiodiagnóstico que mayor dosis de radiación emite. En los últimos años ha aumentado mucho su uso en la práctica médica y, por ello, hemos querido estudiar en este trabajo la dosis de radiación procedente de los TC que recibe la población en España Tras analizar los datos recopilados de los centros hospitalarios de todas las Comunidades Autónomas Españolas y basándonos en los principales tipos de procedimiento de TC referenciados en el Report Radiation Protection nº154, hemos estimado los valores de referencia de dosis (DRLs) (3ºquartil) para los procedimientos que mayor contribución aportan a la dosis colectiva, por encima de 1000 hombre-Sv. Se ha tenido en cuenta la dosis por longitud (DLP). Los DRLs estimados han sido (mGy*cm) son TC cabeza 450, TC tórax 490, TC columna 690, TC abdomen 750, TC pelvis 780 y TC tronco 890. Los resultados obtenidos confirmaron que más de la mitad de la Dosis Efectiva Colectiva (dosis poblacional), el 66%, depende de las Tomografías Computarizadas, 645,23 mSv/1000 habitantes para un total global de todos los estudios con RX de 969,35 mSv/1000 habitantes. Por lo tanto, es importante intentar disminuir la exposición de la población a la radiación, haciendo un buen uso de las nuevas tecnologías e incluyendo la Protección Radiológica en la práctica médica

Caracterización de la ganadería bovina en el área de protección de flora y fauna cañón del Usumacinta, Tenosique, Tabasco, México

Objective: Bovine Production Systems were characterized in the ejidos of the Flora and Fauna Protection Area, Usumacinta Canyon, Tenosique Tabasco. Design/methodology/approach: Socioeconomic strata Were created for the production units by a random sampling to 80 Units of Bovine Production, contingency tables were generated with tests of X2 and for categorical data and Analysis of Variance (ANOVA) for quantitative data. Results: A bovine production system was identified: "Traditional Extensive", in three strata (I. Agriculture and Conservation, II.Agriculture and Livestock, and III. Livestock), where the socioeconomic, physiographic and market level affect its technology and production. Limitations on study/implications: The Traditional Extensive System presents strong limitations to create strategies for the improvement of the production due to the physiography it puts in disadvantage the technification and development, that affect the marketing channels and due to this, there is persistence of jungle vegetation. Findings/conclusions: The production units must lay the foundations in the sustainable use of resources through the development of a livestock from a territorial ordering perspective.Objetivo: Se caracterizaron los Sistemas de Producción Bovina en los ejidos del Área de Protección de Flora y Fauna, Cañón del Usumacinta, Tenosique Tabasco. Diseño/metodología/aproximación: Se crearon estratos socioeconómicos para las unidades de producción  mediante un muestro aleatorio a 80 Unidades de Producción Bovina, se generaron tablas de contingencia con pruebas de X2 y para datos categóricos y Análisis de Varianza (ANOVA) para datos cuantitativos. Resultados: Se identificó un sistema de producción bovina: “Extensivo Tradicional”, en tres estratos (I. Agricultura y Conservación, II. Agricultura y Ganadería, y III. Ganadería), donde el nivel socioeconómico, fisiográfico y el mercado afectan su tecnología y producción. Limitaciones del estudio/implicaciones: El Sistema Extensivo Tradicional presenta fuertes limitaciones para crear estrategias para la mejora de la producción debido a la fisiografía pone en desventaja la tecnificación y desarrollo, que afectan a los canales de comercialización y debido a esto, existe persistencia de vegetación selvática. Hallazgos/conclusiones: Las unidades de producción deben sentar las bases en el aprovechamiento sostenible de los recursos mediante el desarrollo de una ganadería desde una perspectiva de ordenamiento territorial