The Chemical Composition of Cernis 52 (BD+31 640)

We present an abundance analysis of the star Cernis 52 in whose spectrum we recently reported the napthalene cation in absorption at 6707.4 {\AA}. This star is on a line of sight to the Perseus molecular complex. The analysis of high-resolution spectra using a chi^2-minimization procedure and a grid of synthetic spectra provides the stellar parameters and the abundances of O, Mg, Si, S, Ca, and Fe. The stellar parameters of this star are found to be T_{eff} = 8350 +- 200 K, logg= 4.2 +- 0.4 dex. We derived a metallicity of [Fe/H] = -0.01 +- 0.15. These stellar parameters are consistent with a star of $\sim 2$ \Msun in a pre-main-sequence evolutionary stage. The stellar spectrum is significantly veiled in the spectral range 5150-6730 {\AA} up to almost 55 per cent of the total flux at 5150 {\AA} and decreasing towards longer wavelengths. Using Johnson-Cousins and 2MASS photometric data, we determine a distance to Cernis 52 of 231$^{+135}_{-85}$ pc considering the error bars of the stellar parameters. This determination places the star at a similar distance to the young cluster IC 348. This together with its radial velocity, v_r=13.7+-1 km/s, its proper motion and probable young age support Cernis 52 as a likely member of IC 348. We determine a rotational velocity of v\sin i=65 +- 5 km/s for this star. We confirm that the stellar resonance line of \ion{Li}{1} at 6707.8 {\AA} is unable to fit the broad feature at 6707.4 {\AA}. This feature should have a interstellar origin and could possibly form in the dark cloud L1470 surrounding all the cluster IC 348 at about the same distance.Comment: Accepted for publication in The Astrophysical Journa

S wave velocity structure below central Mexico using high-resolution surface wave tomography

Shear wave velocity of the crust below central Mexico is estimated using surface wave dispersion measurements from regional earthquakes recorded on a dense, 500 km long linear seismic network. Vertical components of regional records from 90 well-located earthquakes were used to compute Rayleigh-wave group-velocity dispersion curves. A tomographic inversion, with high resolution in a zone close to the array, obtained for periods between 5 and 50 s reveals significant differences relative to a reference model, especially at larger periods (>30 s). A 2-D S wave velocity model is obtained from the inversion of local dispersion curves that were reconstructed from the tomographic solutions. The results show large differences, especially in the lower crust, among back-arc, volcanic arc, and fore-arc regions; they also show a well-resolved low-velocity zone just below the active part of the Trans Mexican Volcanic Belt (TMVB) suggesting the presence of a mantle wedge. Low densities in the back arc, inferred from the low shear wave velocities, can provide isostatic support for the TMVB

Results for the Spanish Survey in the NAFO Regulatory Area of Division 3L for the period 2003-2018

Since 2003, a stratified random summer bottom trawl survey was conducted by Spain in the NAFO Regulatory Area of Division 3L (Flemish Pass). The surveys were carried out by the R/V “Vizconde de Eza” using bottom trawl net type Campelen 1800. Entire series of mean catches, biomass and length distribution for Greenland halibut, American plaice and witch flounder are presented for the period 2003-2018. Greenland halibut biomass and abundance estimates presented an increasing trend since 2011, reaching in 2017 the highest value of the entire time-series. In 2018, the biomass shows a decrease. For American plaice biomass and abundance estimates show an increasing trend since 2010, reaching in 2015 the highest value in the series; since 2016, all indices decreased. Regarding witch flounder, the biomass and abundance show no a clear trend in the whole period, reaching the maximum of the series in 2010 and 2015. The 2018 biomass estimate continue the declining trend observed in 2016

Results for the Spanish Survey in the NAFO Regulatory Area of Division 3L for the period 2003-2019

Since 2003, a stratified random summer bottom trawl survey was conducted by Spain in the NAFO Regulatory Area of Division 3L (Flemish Pass). The surveys were carried out by the R/V “Vizconde de Eza” using bottom trawl net type Campelen 1800. Entire series of mean catches, biomass and length distribution for Greenland halibut, American plaice and witch flounder are presented for the period 2003-2019. Greenland halibut biomass and abundance estimates presented an increasing trend since 2011, reaching in 2017 the highest value of the entire time-series. In 2019, the biomass shows a slight increase. For American plaice biomass and abundance estimates show an increasing trend since 2010, reaching in 2015 the highest value in the series; since 2016, all indices decreased. Regarding witch flounder, the biomass and abundance show no a clear trend in the whole period, reaching the maximum of the series in 2010 and 2015. The 2019 biomass estimate continue the declining trend observed in 2016

A search for interstellar anthracene toward the Perseus anomalous microwave emission region

We report the discovery of a new broad interstellar (or circumstellar) band at 7088.8 +- 2.0 \AA coincident to within the measurement uncertainties with the strongest band of the anthracene cation (C$_{14}$H$_{10}$$^+$) as measured in gas-phase laboratory spectroscopy at low temperatures (Sukhorukov et al.2004). The band is detected in the line of sight of star Cernis 52, a likely member of the very young star cluster IC 348, and is probably associated with cold absorbing material in a intervening molecular cloud of the Perseus star forming region where various experiments have recently detected anomalous microwave emission. From the measured intensity and available oscillator strength we find a column density of N$_{an^+}$= 1.1(+-0.4) x 10$^{13}$ cm$^{-2}$ implying that ~0.008% of the carbon in the cloud could be in the form of C$_{14}$H$_{10}$$^+$. A similar abundance has been recently claimed for the naphthalene cation (Iglesias-Groth et al. 2008) in this cloud. This is the first location outside the Solar System where specific PAHs are identified. We report observations of interstellar lines of CH and CH$^+$ that support a rather high column density for these species and for molecular hydrogen. The strength ratio of the two prominent diffuse interstellar bands at 5780 and 5797 \AA suggests the presence of a ``zeta'' type cloud in the line of sight (consistent with steep far-UV extinction and high molecular content). The presence of PAH cations and other related hydrogenated carbon molecules which are likely to occur in this type of clouds reinforce the suggestion that electric dipole radiation from fast spinning PAHs is responsible of the anomalous microwave emission detected toward Perseus.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Evidence for the naphthalene cation in a region of the interstellar medium with anomalous microwave emission

We report high resolution spectroscopy of the moderately reddened (A$_V$=3) early type star Cernis 52 located in a region of the Perseus molecular cloud complex with anomalous microwave emission. In addition to the presence of the most common diffuse interstellar bands (DIBs) we detect two new interstellar or circumstellar bands coincident to within 0.01% in wavelength with the two strongest bands of the naphthalene cation (C$_{10}$H$_{8}^+$) as measured in gas-phase laboratory spectroscopy at low temperatures and find marginal evidence for the third strongest band. Assuming these features are caused by the naphthalene cation, from the measured intensity and available oscillator strengths we find that 0.008 % of the carbon in the cloud could be in the form of this molecule. We expect hydrogen additions to cause hydronaphthalene cations to be abundant in the cloud and to contribute via electric dipole radiation to the anomalous microwave emission. The identification of new interstellar features consistent with transitions of the simplest polycyclic aromatic hydrocarbon adds support to the hypothesis that this type of molecules are the carriers of both diffuse interstellar bands and anomalous microwave emission.Comment: Accepted for publication in The Astrophysical Journa

Resultados prácticos de la aplicación de estándares industriales a la interoperabilidad en el regadío: Proyecto Mega

La falta de estandarización en los sistemas de telecontrol de regadío dificulta enormemente la gestión y el mantenimiento de los mismos, pero no menos importante es reconocer que dificulta la explotación de las propias infraestructuras modernizadas. El proyecto MEGA define los criterios para establecer interoperabilidad entre los diferentes sistemas de control y gestión que se emplean en el regadío. Dicha interoperabilidad se basa en el establecimiento de una nueva arquitectura de control a través de la cual se comuniquen los diferentes sistemas mediante un lenguaje de modelización desarrollado exprofeso. El desarrollo teórico de la modelización y el diseño de la nueva arquitectura tienen un largo recorrido y son conocidos por todo el sector. Se pretende presentar a continuación cómo se ha procedido a la validación empírica de esas bases teóricas estableciéndose una interoperabilidad real entre diferentes sistemas, participando en las pruebas diferentes agentes del sector del regadío.The lack of standardization of telecontrol systems for irrigation complicates their management and maintenance as well as the exploitation of modernized infrastructures. The MEGA project defines the criteria for establishing interoperability between different control and management systems used in irrigation. Such interoperability is based on the establishment of a new control architecture enabling the communication of various systems by a modeling language developed for this purpose. The theoretical development of modeling and design of the new architecture have a long way and are known throughout the sector. In this work we present the procedure to empirical validation of these theoretical bases, establishing a real interoperability between different systems, participating different operators from the irrigation sector in the testing

Experiencia en el desarrollo de una herramienta para la enseñanza de comunicaciones digitales en carreras de Informática

Este trabajo presenta una herramienta de aprendizaje asistido por banco de pruebas formada por tres elementos: plataforma hardware, arquitectura de software multicapa y herramienta gráfica (gtTAL). Para el desarrollo de la herramienta se ha optado por una arquitectura multicapa donde el nivel más alto es una interfaz gráfica que permite la interacción con la plataforma sin necesidad de tener conocimientos de programación de hardware a bajo nivel. Por tanto, los estudiantes pueden testear algoritmos fácilmente sin desarrollar un nuevo programa desde cero, reduciendo significativamente el tiempo empleado para las tareas de implementación y optimización.Peer Reviewe

Magnetic Field scaling of Relaxation curves in Small Particle Systems

We study the effects of the magnetic field on the relaxation of the magnetization of small monodomain non-interacting particles with random orientations and distribution of anisotropy constants. Starting from a master equation, we build up an expression for the time dependence of the magnetization which takes into account thermal activation only over barriers separating energy minima, which, in our model, can be computed exactly from analytical expressions. Numerical calculations of the relaxation curves for different distribution widths, and under different magnetic fields H and temperatures T, have been performed. We show how a \svar scaling of the curves, at different T and for a given H, can be carried out after proper normalization of the data to the equilibrium magnetization. The resulting master curves are shown to be closely related to what we call effective energy barrier distributions, which, in our model, can be computed exactly from analytical expressions. The concept of effective distribution serves us as a basis for finding a scaling variable to scale relaxation curves at different H and a given T, thus showing that the field dependence of energy barriers can be also extracted from relaxation measurements.Comment: 12 pages, 9 figures, submitted to Phys. Rev.

Results for the Atlantic cod, roughhead grenadier, redfish, thorny skate and black dogfish of the Spanish Survey in the NAFO Div. 3L for the period 2003-2016

Since 2003, a stratified random spring bottom trawl survey was conducted by Spain in Division 3L of NAFO Regulatory Area (Flemish Pass). The surveys were carried out by the R/V “Vizconde de Eza” using bottom trawl net type Campelen. Entire series of mean catches, biomass and length distribution for Atlantic cod, roughhead grenadier, redfish, thorny skate and black dogfish are presented for the period 2003-2016.Postprin