1,961 research outputs found
Probing the Circumnuclear Stellar Populations of Starburst Galaxies in the Near-infrared
We employ the NASA Infrared Telescope Facility's near-infrared spectrograph
SpeX at 0.8-2.4m to investigate the spatial distribution of the stellar
populations (SPs) in four well known Starburst galaxies: NGC34, NGC1614,
NGC3310 and NGC7714. We use the STARLIGHT code updated with the synthetic
simple stellar populations models computed by Maraston (2005, M05). Our main
results are that the NIR light in the nuclear surroundings of the galaxies is
dominated by young/intermediate age SPs (yr), summing from
40\% up to 100\% of the light contribution. In the nuclear aperture of
two sources (NGC1614 and NGC3310) we detected a predominant old SP component
(yr), while for NGC34 and NGC7714 the younger component
prevails. Furthermore, we found evidence of a circumnuclear star formation
ring-like structure and a secondary nucleus in NGC1614, in agreement with
previous studies. We also suggest that the merger/interaction experienced by
three of the galaxies studied, NGC1614, NGC3310 and NGC7714 can explain the
lower metallicity values derived for the young SP component of these sources.
In this scenario the fresh unprocessed metal poorer gas from the
destroyed/interacting companion galaxy is driven to the centre of the galaxies
and mixed with the central region gas, before star formation takes place. In
order to deepen our analysis, we performed the same procedure of SP synthesis
using Maraston (2011, M11) EPS models. Our results show that the newer and
higher resolution M11 models tend to enhance the old/intermediate age SP
contribution over the younger ages
Assessment of mesial temporal sclerosis through MRI processing
[EN] Mesial temporal sclerosis (MTS) is the principal cause of complex epilepsy, is manifested principally by gliosis and hippocampal volume loss. This project aims to develop an algorithm that allows automatic measurement of hippocampal volume and signal intensity in magnetic resonance imaging. The algorithm developed uses preprocessing of the images to reduce the artifacts and for the extraction of the features were used techniques of machine learning (support vector machine) and texture analysis. Results can help to optimize time in the assessment of the mesial temporal sclerosis and can contribute to the best training to the youngers neuroradiologists.Castillo-Malla, DP.; Samaniego, R.; Jimenez-Gaona, Y.; Sánchez, A.; Carrión, J.; Rodríguez-Álvarez, MJ. (2020). Assessment of mesial temporal sclerosis through MRI processing. Proceedings of SPIE (Online). 1-7. https://doi.org/10.1117/12.2569043S1
Instituto Internacional de Investigaci ́on e Innovaci ́on del Envejecimiento
El Instituto Internacional de Investigaci on e Innovaci on del
Envejecimiento es un proyecto transfronterizo y multidisciplinar centrado en la mejora de la calidad de vida de los ancianos mediante el uso de la tecnolog a. En este proyecto colaboran la Universidad de Evora, el Instituto Polit ecnico de Porto Alegre, el Instituto Polit ecnico de Beja, la Administraci on Regional de Salud de Alentejo y la Universidad de Extremadura. Los objetivos del proyecto se centran en comprender los aspectos biom edicos, funcionales y psicol ogicos del envejecimiento; generar nuevos modelos y procesos de cuidado a ancianos y desarrollar soluciones tecnol ogicas que contribuyan a la salud y calidad de vida de los ancianos y a la sostenibilidad de los servicios
The pulsating hot subdwarf Balloon 090100001: results of the 2005 multisite campaign
We present the results of a multisite photometric campaign on the pulsating
sdB star Balloon 090100001. The star is one of the two known hybrid hot
subdwarfs with both long- and short-period oscillations. The campaign involved
eight telescopes with three obtaining UBVR data, four B-band data, and one
Stromgren uvby photometry. The campaign covered 48 nights, providing a temporal
resolution of 0.36microHz with a detection threshold of about 0.2mmag in
B-filter data.
Balloon 090100001 has the richest pulsation spectrum of any known pulsating
subdwarf B star and our analysis detected 114 frequencies including 97
independent and 17 combination ones. The strongest mode (f_1) in the 2.8mHz
region is most likely radial while the remaining ones in this region form two
nearly symmetric multiplets: a triplet and quintuplet, attributed to
rotationally split \ell=1 and 2 modes, respectively. We find clear increases of
splitting in both multiplets between the 2004 and 2005 observing campaigns,
amounting to 15% on average. The observed splittings imply that the rotational
rate in Bal09 depends on stellar latitude and is the fastest on the equator. We
use a small grid of models to constrain the main mode (f_1), which most likely
represents the radial fundamental pulsation. The groups of p-mode frequencies
appear to lie in the vicinity of consecutive radial overtones, up to the third
one. Despite the large number of g-mode frequencies observed, we failed to
identify them, most likely because of the disruption of asymptotic behaviour by
mode trapping. The observed frequencies were not, however, fully exploited in
terms of seismic analysis which should be done in the future with a larger grid
of reliable evolutionary models of hot subdwarfs.Comment: accepted for publication in MNRA
Transcriptomic profiling of TK2 deficient human skeletal muscle suggests a role for the p53 signalling pathway and identifies growth and differentiation factor-15 as a potential novel biomarker for mitochondrial myopathies
Background
Mutations in the gene encoding thymidine kinase 2 (TK2) result in the myopathic form of mitochondrial DNA depletion syndrome which is a mitochondrial encephalomyopathy presenting in children. In order to unveil some of the mechanisms involved in this pathology and to identify potential biomarkers and therapeutic targets we have investigated the gene expression profile of human skeletal muscle deficient for TK2 using cDNA microarrays.
Results
We have analysed the whole transcriptome of skeletal muscle from patients with TK2 mutations and compared it to normal muscle and to muscle from patients with other mitochondrial myopathies. We have identified a set of over 700 genes which are differentially expressed in TK2 deficient muscle. Bioinformatics analysis reveals important changes in muscle metabolism, in particular, in glucose and glycogen utilisation, and activation of the starvation response which affects aminoacid and lipid metabolism. We have identified those transcriptional regulators which are likely to be responsible for the observed changes in gene expression.
Conclusion
Our data point towards the tumor suppressor p53 as the regulator at the centre of a network of genes which are responsible for a coordinated response to TK2 mutations which involves inflammation, activation of muscle cell death by apoptosis and induction of growth and differentiation factor 15 (GDF-15) in muscle and serum. We propose that GDF-15 may represent a potential novel biomarker for mitochondrial dysfunction although further studies are required
First direct detection of an exoplanet by optical interferometry; Astrometry and K-band spectroscopy of HR8799 e
To date, infrared interferometry at best achieved contrast ratios of a few
times on bright targets. GRAVITY, with its dual-field mode, is now
capable of high contrast observations, enabling the direct observation of
exoplanets. We demonstrate the technique on HR8799, a young planetary system
composed of four known giant exoplanets. We used the GRAVITY fringe tracker to
lock the fringes on the central star, and integrated off-axis on the HR8799e
planet situated at 390 mas from the star. Data reduction included
post-processing to remove the flux leaking from the central star and to extract
the coherent flux of the planet. The inferred K band spectrum of the planet has
a spectral resolution of 500. We also derive the astrometric position of the
planet relative to the star with a precision on the order of 100as. The
GRAVITY astrometric measurement disfavors perfectly coplanar stable orbital
solutions. A small adjustment of a few degrees to the orbital inclination of HR
8799 e can resolve the tension, implying that the orbits are close to, but not
strictly coplanar. The spectrum, with a signal-to-noise ratio of
per spectral channel, is compatible with a late-type L brown dwarf. Using
Exo-REM synthetic spectra, we derive a temperature of \,K and a
surface gravity of cm/s. This corresponds to a radius
of and a mass of , which is an independent confirmation of mass estimates from evolutionary
models. Our results demonstrate the power of interferometry for the direct
detection and spectroscopic study of exoplanets at close angular separations
from their stars.Comment: published in A&
Regulación de la expresión de IL-33 e IL-17 por la modulación farmacológica de HIF-1 en un modelo murino de inflamación alérgica pulmonar
Objetivo: Evaluar el efecto de la modulación farmacológica de HIF-1 en la expresión de IL-33 e IL-17 en un modelo murino de inflamación alérgica pulmonar (IAP) con diferentes grados de severidad.
Métodos: 5 ratones/grupo recibieron ovoalbúmina (OVA) 1(leve), 2(moderada) o 3(severa) retos vía i.t. previa sensibilización como alergeno, además los grupos de inducción o inhibición de HIF-1α, recibieron EDHB (OVA+EDHB) i.p. o 2ME (OVA+2ME) i.t. respectivamente. Los grupos controles recibieron solución salina (SS) de igual forma. Se realizaron tinciones de HE (infiltrado inflamatorio), PAS (producción de moco) e inmunohistoquímicas de HIF-1α, IL-33, IL-17, analizando cuantitativamente por patología digital.
Resultados: Obtuvimos diferentes grados de severidad a mayor número de retos, incrementando la expresión de HIF-1, correlacionando con la expresión de IL- 33/IL-17. Aumentando o disminuyendo, respectivamente por la modulación farmacológica.
Conclusiones: Lo anterior sugiere que la alta expresión de HIF-1 favorece la producción de IL-33 e IL-17 contribuyendo al daño en el tejido pulmonar y la severidad de la enfermedad y estas pueden ser reguladas a través de la modulación de HIF-1
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