3,857 research outputs found
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
ComunicaciĂłn 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 worldâs 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·Ï·T)/Îș ,where S, Ï, Îș, and T stand for the Seebeck coefficient, electrical and thermal conductivities, and the
absolute temperature, respectively. Given that in classical physics S, Ï, and Îș, 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 Îș 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 AndalucĂa. III.
 New data on the Andalusian flora. III.Palabras clave. Flora, corologĂa, Sierra Tejeda, Sierra Almijara, MĂĄlaga, Granada, AndalucĂa, España.Key words. flora, chorology, Tejeda, Almijara, Malaga, Granada, Andalusia, Spain
Fasciola hepatica induces Foxp3 T cell, proinflammatory and regulatory cytokine overexpression in liver from infected sheep during early stages of infection
The expression of T regulatory cells (Foxp3), regulatory (interleukin [IL]-10 and transforming growth factor beta [TGF-ÎČ]) and proinflammatory (tumor necrosis factor alpha [TNF-α] and interleukin [IL]-1ÎČ) cytokines was quantified using real time polymerase chain reaction (qRT-PCR) in the liver of sheep during early stages of infection with Fasciola hepatica (1, 3, 9, and 18 days post-infection [dpi]). Portal fibrosis was also evaluated by Massonâs trichrome stain as well as the number of Foxp3+ cells by immunohistochemistry. Animals were divided into three groups: (a) group 1 was immunized with recombinant cathepsin L1 from F. hepatica (FhCL1) in Montanide adjuvant and infected; (b) group 2 was uniquely infected with F. hepatica; and (c) group 3 was the control group, unimmunized and uninfected. An overexpression of regulatory cytokines of groups 1 and 2 was found in all time points tested in comparison with group 3, particularly at 18 dpi. A significant increase of the number of Foxp3+ lymphocytes in groups 1 and 2 was found at 9 and 18 dpi relative to group 3. A progressive increase in portal fibrosis was found in groups 1 and 2 in comparison with group 3. In this regard, group 1 showed smaller areas of fibrosis than group 2. There was a significant positive correlation between Foxp3 and IL-10 expression (by immunohistochemistry and qRT-PCR) just as between portal fibrosis and TGF-ÎČ gene expression. The expression of proinflammatory cytokines increased gradually during the experience. These findings suggest the induction of a regulatory phenotype by the parasite that would allow its survival at early stages of the disease when it is more vulnerable.This work was supported by EU Grant (H2020-635408-PARAGONE) and National grant (AGL2015-67023-C2-1-R). We thank Prof. John P. Dalton, Queenâs University Belfast, Northern Ireland, for providing recombinant FhCL1. Sequencing analysis and quality analysis of RNA were carried out by the Cenâ tral Services for Research of the University of CĂłrdoba (SCAI).Veterinari
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 RamĂłn y Cajal program (RYC-2011-08521
Aportaciones a la flora de AndalucĂa. II.
New data on the Andalusian flora. II. Palabras clave. Juniperus, Dryopteris, Moehringia, Ulex, Fran gula, Lithodora, Atropa, flora, corologĂa, AndalucĂa, 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 huĂ©sped intermediario para cumplir su ciclo: ganado porcino y ganado bovino respectivamente. El hombre es el huĂ©sped definitivo en el cual se desarrolla la forma adulta. La clĂnica principal de Taenia saginata es digestiva, mientras que Taenia solium puede afectar a otros tejidos. Se presenta el caso de una adolescente que elimina parĂĄsitos en la ropa interior y heces sin otro sĂntoma. Los describen como gusanos blancos, planos y mĂłviles. En la anamnesis refiere que le gustan los chuletones de carne poco cocinada, pero sin concretar un posible foco de la infestaciĂłn. Se realiza un anĂĄlisis con resultado normal, excepto una eosinofilia de 9,6%. En el laboratorio de MicrobiologĂa, por visiĂłn directa tras tinciĂłn con tinta china y reacciĂłn en cadena de la polimerasa directa se confirma el diagnĂłstico de Taenia saginata. Tras el resultado, se le indica tratamiento con prazicuantel vĂa oral en dosis Ășnica (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
ContribucioÌn al conocimiento de la flora del Parque Natural de las sierras Tejeda, Almijara y Alhama (MaÌlaga-Granada, EspanÌa).
RESUMEN. ContribuciĂłn al conocimiento de la flora del Parque Natural de las sierras Tejeda, Almijara y Alhama (MĂĄlaga-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 MĂĄlaga, recolectados, la mayorĂa de ellos, durante los años 2003 y 2004. Se citan 1.176 especies y subespecies, indicando para cada una de ellas provincia, tĂ©rmino municipal y UTM. Se señalan las especies amenazadas segĂșn criterios UICN y Junta de AndalucĂa.Palabras clave. Flora, especies amenazadas, Sierra Tejeda, Sierra de Alhama, Sierra Almijara, MĂĄlaga, 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.
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