A multi-wavelength view of the central kiloparsec region in the Luminous Infrared Galaxy NGC1614

The Luminous Infrared Galaxy NGC1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Pa-alpha, optical, and X-ray observations of NGC1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array (VLA) and the Gemini/T-ReCS 8.7 micron emission, as well as the Pa-alpha line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used an HST/NICMOS Pa-alpha map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power-law for each individual region within the central kpc of NGC1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an AGN, but rather by a compact (r < 90 pc) starburst. Chandra X-ray data also show that the central kpc region is dominated by starburst activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the starburst ring and a putative AGN in NGC1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.Comment: 13 pages, 7 figures, 5 tables. Accepted for publication in Ap

Optimization of bismuth telluride films and nano-wire arrays via electrodeposition for thermoelectric applications

Comunicación presentada en el 3rd Early Stage Researchers Workshop in Nanoscience, celebrado en Madrid el 27 y 28 de junio de 2013.Due to the current world’s demand for energy, there is a great interest in thermoelectricity, which offers the possibility of increasing the sustainability of our electrical system. Thermoelectric materials can convert heat into electricity and vice versa, and thus they offer a way of recovering wasted heat produced in engines, industrial processes and others into usable power. However, one of the main problems for their actual use is their low efficiency in this conversion. This efficiency is directly related with what is called the thermoelectric figure of merit, described by ZT=(S2·σ·T)/κ ,where S, σ, κ, and T stand for the Seebeck coefficient, electrical and thermal conductivities, and the absolute temperature, respectively. Given that in classical physics S, σ, and κ, are correlated, the improvement of the efficiency is not straightforward. Nevertheless, in 1993 a theoretical work suggested that the efficiency could be greatly enhanced by reducing the dimensionality of the structures under studied and working in the nano-scale. Therefore, much experimental effort has been done to achieve these kind of structures and in some cases, an enhancement of the ZT value has been achieved, although this has not been due to the quantum confinement to the charge carriers, as it was theoretically predicted, but to an increase of the κ due to the increased number of interface boundaries in nanostructures. Among the most efficient thermoelectric materials used for applications at room temperature, bismuth telluride (Bi2Te3) and its different alloys stand out, with a ZT for Bi2Te3of around 1 at RT [2]. We present here an optimized method of obtaining films and nanowire arrays via electrochemical deposition in a conventional three-electrode cell. Different ways of improving the quality of the obtained films have been studied (working electrode, constant and pulsed potentials, different chemical baths, etc.) in order to obtain highly oriented (110) films, which are the most favorable for out-of-plane applications. Then, nanostructuration has been achieved by changing the working electrode to porous alumina templates and realizing the electrochemical deposition inside the pores. The samples produced have been characterized using SEM, EDX, AFM, XRD, and Raman spectrometry, and in the case of the films, their transport properties have also been measured.Peer Reviewe

Aportaciones a la flora de Andalucía. III.

 New data on the Andalusian flora. III.Palabras clave. Flora, corología, Sierra Tejeda, Sierra Almijara, Málaga, Granada, Andalucía, España.Key words. flora, chorology, Tejeda, Almijara, Malaga, Granada, Andalusia, Spain

Wide band-gap tuning Cu2ZnSn1-xGexS4 single crystals: Optical and vibrational properties

The linear optical properties of Cu2ZnSn1-xGe x S4 high quality single crystals with a wide range of Ge contents (x=0.1, 0.3, 0.5, 0.7, 0.9 and 1) have been investigated in the ultraviolet and near infrared range using spectroscopic ellipsometry measurements. From the analysis of the complex dielectric function spectra it has been found that the bandgap E 0 increases continuously from 1.49eV to 2.25eV with the Ge content. Furthermore, the evolution of the interband transitions E 1A and E 1B has been also determined. Raman scattering using three different excitation wavelengths and its analysis have been performed to confirm the absence of secondary phases in the samples, and to distinguish between stannite, wurtzite, wurzstannite and kesterite structures. Additionally, the analysis of the high resolution Raman spectra obtained in samples with different [Ge]/([Ge]+[Sn]) ratios allows describing a bimodal behavior of the dominant A modes. The understanding of the incorporation of Ge into the Cu2ZnSnS4 lattice is fundamental in order to develop efficient bandgap engineering of these compounds towards the fabrication of kesterite based solar cells with enhanced performanceThis work was supported by the Marie Curie-ITN project (KESTCELL, GA: 316488), Marie Curie-IRSES project (PVICOKEST, GA: 269167), AMALIE (TEC2012-38901-C02-01) and SUNBEAM (ENE2013-49136-C4-3-R) project funded by the Spanish Ministry of Economy and Competitiveness. RC acknowledges financial support from Spanish MINECO within the Ramón y Cajal program (RYC-2011-08521

Aportaciones a la flora de Andalucía. II.

New data on the Andalusian flora. II. Palabras clave. Juniperus, Dryopteris, Moehringia, Ulex, Fran gula, Lithodora, Atropa, flora, corología, Andalucía, España.Key words. Juniperus, Dryopteris, Moehringia, Ulex, Fran gula, Lithodora, Atropa, flora, chorology, Andalusia, Spain

Taenia saginata en una adolescente

La teniasis es una parasitosis intestinal causada por la forma adulta de los cestodos (gusanos planos). En el ser humano se presentan dos especies, Taenia solium y Taenia saginata, ambas hermafroditas y que requieren un huésped intermediario para cumplir su ciclo: ganado porcino y ganado bovino respectivamente. El hombre es el huésped definitivo en el cual se desarrolla la forma adulta. La clínica principal de Taenia saginata es digestiva, mientras que Taenia solium puede afectar a otros tejidos. Se presenta el caso de una adolescente que elimina parásitos en la ropa interior y heces sin otro síntoma. Los describen como gusanos blancos, planos y móviles. En la anamnesis refiere que le gustan los chuletones de carne poco cocinada, pero sin concretar un posible foco de la infestación. Se realiza un análisis con resultado normal, excepto una eosinofilia de 9,6%. En el laboratorio de Microbiología, por visión directa tras tinción con tinta china y reacción en cadena de la polimerasa directa se confirma el diagnóstico de Taenia saginata. Tras el resultado, se le indica tratamiento con prazicuantel vía oral en dosis única (medicamento off-label), sin presentar efectos secundarios. Taeniasis is an intestinal parasitic infection due to an adult worm of tapeworms (cestodes). In humans, there are two main species: Taenia solium and Taenia saginata, both of them are hermaphrodites and require an intermediate host to complete their life circle: pigs beef tapeworm (Taenia saginata) and pork tapeworm (Taenia solium). Humans are the only definitive hosts in which the adult form develops. Taenia saginata mainly causes gastrointestinal symptoms, while Taenia solium can affect other tissues. We report the case of a teenager who found a number of adult worms on her intimate clothes and in her stools without any other symptom. The worms were described as flat, white and mobile. At the review, she said that she loved eating undercooked meat without determining the source of the infection. We detected high eosinophilia level in blood test (9, 6%). A microbiological test identified proglottids in the stool with a direct examination, and polymerase chain reaction methods established a species diagnosis of Taenia saginata. As a result, we started treatment with prazicuantel orally single dose (off-label) without presenting any side effects

Theoretical analysis of the focusing of acoustic waves by two-dimensional sonic crystals

Motivated by a recent experiment on acoustic lenses, we perform numerical calculations based on a multiple scattering technique to investigate the focusing of acoustic waves with sonic crystals formed by rigid cylinders in air. The focusing effects for crystals of various shapes are examined. The dependance of the focusing length on the filling factor is also studied. It is observed that both the shape and filling factor play a crucial role in controlling the focusing. Furthermore, the robustness of the focusing against disorders is studied. The results show that the sensitivity of the focusing behavior depends on the strength of positional disorders. The theoretical results compare favorably with the experimental observations, reported by Cervera, et al. (Phys. Rev. Lett. 88, 023902 (2002)).Comment: 8 figure

Contribución al conocimiento de la flora del Parque Natural de las sierras Tejeda, Almijara y Alhama (Málaga-Granada, España).

RESUMEN. Contribución al conocimiento de la flora del Parque Natural de las sierras Tejeda, Almijara y Alhama (Málaga-Granada, España). Se ha realizado un estudio sobre la diversidad vegetal de las sierras Tejeda, Almijara y Alhama. Se han identificado cerca de 10.000 pliegos depositados en el Herbario MGC de la Universidad de Málaga, recolectados, la mayoría de ellos, durante los años 2003 y 2004. Se citan 1.176 especies y subespecies, indicando para cada una de ellas provincia, término municipal y UTM. Se señalan las especies amenazadas según criterios UICN y Junta de Andalucía.Palabras clave. Flora, especies amenazadas, Sierra Tejeda, Sierra de Alhama, Sierra Almijara, Málaga, Granada, España.SUMMARY. Contribution to the flora of the Natural Park of Tejeda, Almijara and Alhama mountain ranges (Malaga-Granada, Spain). A survey on the flora diversity in the Tejeda, Almijara and Alhama mountain ranges has been carried out. About 10.000 herbarium sheets have been identified and kept in the MGC (Herbarium of the University of Malaga). In most cases the specimens were collected during the years 2003 and 2004. 1.176 taxa (species and subspecies) are cited and some data such as province, municipality and UTM are given for every one. Endangered species are pointed out, following the UICN and Andalusia Government criteria.Key words. Flora, endangered species, Sierra Tejeda, Sierra de Alhama, Sierra Almijara, Malaga, Granada, Spain

Candidate free-floating super-Jupiters in the young sigma Orionis open cluster

Free-floating substellar candidates with estimated theoretical masses of as low as ~5 Jupiter masses have been found in the ~3 Myr old sigma Orionis open cluster. As the overlap with the planetary mass domain increases, the question of how these objects form becomes important. The determination of their number density and whether a mass cut-off limit exists is crucial to understanding their formation. We propose to search for objects of yet lower masses in the cluster and determine the shape of the mass function at low mass. Using new- and (re-analysed) published IZJHKs[3.6]-[8.0]-band data of an area of 840 arcmin2, we performed a search for LT-type cluster member candidates in the magnitude range J=19.5-21.5 mag, based on their expected magnitudes and colours. Besides recovering the T type object S Ori 70 and two other known objects, we find three new cluster member candidates, S Ori 72-74, with J=21 mag and within 12 arcmin of the cluster centre. They have theoretical masses of 4 (-2,+3) M_Jup and are among the least massive free-floating objects detected by direct imaging outside the Solar System. The photometry in archival Spitzer [3.6]-[5.8]-band images infers that S Ori 72 is an L/T transition candidate and S Ori 73 a T-type candidate, following the expected cluster sequence in the mid-infrared. Finally, the L-type candidate S Ori 74 with lower quality photometry is located at 11.8 arcsec (~4250 AU) of a stellar member of sigma Orionis and could be a companion. After contaminant correction in the area complete to J=21.1 mag, we estimate that there remain between zero and two cluster members in the mass interval 6-4 M_Jup. Our result suggests a possible turnover in the substellar mass spectrum below ~6 Jupiter masses, which could be investigated further by wider and deeper photometric surveys.Comment: 15 pages, 13 figures, 5 tables, and appendix containing 5 figures; accepted for publication in AA; v2: 2 minor corrections, in abstract and sect. 2.

Wide band-gap tuning Cu2ZnSn1-xGexS4 single crystals: optical and vibrational properties

The linear optical properties of Cu2ZnSn1-xGexS4 high quality single crystals with a wide range of Ge contents (x = 0.1, 0.3, 0.5, 0.7, 0.9 and 1) have been investigated in the ultraviolet and near infrared range using spectroscopic ellipsometry measurements. From the analysis of the complex dielectric function spectra it has been found that the bandgap E0 increases continuously from 1.49 eV to 2.25 eV with the Ge content. Furthermore, the evolution of the interband transitions E1A and E1B has been also determined. Raman scattering using three different excitation wavelengths and its analysis have been performed to confirm the absence of secondary phases in the samples, and to distinguish between stannite, wurtzite, wurzstannite and kesterite structures. Additionally, the analysis of the high resolution Raman spectra obtained in samples with different [Ge]/([Ge]+[Sn]) ratios allows describing a bimodal behavior of the dominant A modes. The understanding of the incorporation of Ge into the Cu2ZnSnS4 lattice is fundamental in order to develop efficient bandgap engineering of these compounds towards the fabrication of kesterite based solar cells with enhanced performanc