1,189 research outputs found
The software for the robotization of the TROBAR telescope
The Telescopi ROBotic de ARas (TROBAR) is a new robotic facility built at
Aras de Los Olmos (Valencia-Spain). This is a 60cm telescope equipped with a
4kx4k optical camera, corresponding to 30x30 arcmin2 FoV, and it will be
primarily used for a systematic search of Ha emitting stars in the Galactic
Plane to a depth of ~14mag. Both data acquisition and reduction will be
performed automatically. The robotization of data acquisition is now entering
its final phase while the development of the data reduction pipeline has just
started.Comment: 10 pages, 3 figures. Accepted for publication in Advances in
Astronomy - Robotic Astronomy special issu
Hydroxytyrosol, an ingredient of olive oil, reduces triglyceride accumulation and promotes lipolysis in human primary visceral adipocytes during differentiation
Hydroxytyrosol has various pharmacological properties, including anti-oxidative stress and anti-inflammatory activities, preventing hyperglycemia, insulin resistance, and the metabolic syndrome. The present study is focused on the anti-adipogenic and lipolytic activity of hydroxytyrosol on primary human visceral adipocytes. Pre-adipocytes were analyzed after 10 (P10) and 20 (P20) days of treatment during differentiation and after 7 (A7) days of treatment when they reached mature shape. The treatment with hydroxytyrosol extract significantly (P\u2009<\u20090.001) increased apoptosis in P10 and P20 cells in comparison to control and A7 cells; significantly (P\u2009<\u20090.001) reduced triglyceride accumulation in P20 cells compared to P10 and control cells; and significantly (P\u2009<\u20090.001) increased lipolysis in P20 cells in comparison to control cells and A7 mature adipocytes. Hydroxytyrosol-treated P20 cells significantly (P\u2009<\u20090.05) increased expression of genes involved in inhibition of adipogenesis, such as GATA2, GATA3, WNT3A, SFRP5, HES1, and SIRT1. In contrast, genes involved in promoting adipogenesis such as LEP, FGF1, CCND1, and SREBF1 were significantly down-regulated by hydroxytyrosol treatment. These data suggest that hydroxytyrosol promotes lipolysis and apoptotic activity in primary human visceral pre-adipocytes during differentiation and does not affect already mature adipocytes.
\ua9 2016 by the Society for Experimental Biology and Medicine
Using Cumulative Number Densities to Compare Galaxies across Cosmic Time
Comparing galaxies across redshifts at fixed cumulative number density is a
popular way to estimate the evolution of specific galaxy populations. This
method ignores scatter in mass accretion histories and galaxy-galaxy mergers,
which can lead to errors when comparing galaxies over large redshift ranges
(Delta z > 1). We use abundance matching in the LCDM paradigm to estimate the
median change in number density with redshift and provide a simple fit (+0.16
dex per unit Delta z) for progenitors of z = 0 galaxies. We find that galaxy
descendants do not evolve in the same way as galaxy progenitors, largely due to
scatter in mass accretion histories. We also provide estimates for the 1-sigma
range of number densities corresponding to galaxy progenitors and descendants.
Finally, we discuss some limits on number density comparisons, which arise due
to difficulties measuring physical quantities (e.g., stellar mass) consistently
across redshifts. A public tool to calculate number density evolution for
galaxies, as well as approximate halo masses, is available online.Comment: 5 pages, minor revisions to match ApJL accepted version. Code
available at: http://code.google.com/p/nd-redshif
CANDELS Multi-wavelength Catalogs: Source Identification and Photometry in the CANDELS Extended Groth Strip
We present a 0.4–8 μm multi-wavelength photometric catalog in the Extended Groth Strip (EGS) field. This catalog is built on the Hubble Space Telescope (HST) WFC3 and ACS data from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), and it incorporates the existing HST data from the All-wavelength Extended Groth strip International Survey (AEGIS) and the 3D-HST program. The catalog is based on detections in the F160W band reaching a depth of F160W = 26.62 AB (90% completeness, point sources). It includes the photometry for 41,457 objects over an area of ≈206 arcmin^2 in the following bands: HST/ACS F606W and F814W; HST WFC3 F125W, F140W, and F160W; Canada–France–Hawaii Telescope (CFHT)/Megacam u*, g’, r’, i’ and z’ CFHT/WIRCAM J, H, and K_S; Mayall/NEWFIRM J1, J2, J3, H1, H2, and K; Spitzer IRAC 3.6, 4.5, 5.8, and 8.0 μm. We are also releasing value-added catalogs that provide robust photometric redshifts and stellar mass measurements. The catalogs are publicly available through the CANDELS repository
Different anti-adipogenic effects of bio-compounds on primary visceral pre-adipocytes and adipocytes.
Several natural compounds exhibit strong capacity for decreasing triglyceride accumulation, enhancing lipolysis
and inducing apoptosis. The present study reports the anti-adipogenic effects of Silybum marianum (SL), Citrus
aurantium (CA), Taraxacum officinale (TO), resveratrol (RE), Curcuma longa (CU), caffeine (CF), oleuropein
(OL) and docosahexaenoic acid (DHA) in reducing differentiation and increasing lipolysis and apoptosis. Analyses
were performed on human primary visceral pre-adipocytes after 10 (P10) and 20 (P20) days of treatment
during differentiation and on mature adipocytes after 7 days of treatment (A7). The percentage of apoptosis induced
by TO extract in P10 and P20 cells was significantly higher than that induced by all other compounds and
in CTRL cells. Triglyceride accumulation was significantly lower in cells treated with DHA, CF, RE in comparison
to cells treated with OL and in CTRL cells. Treatments with CF, DHA and OL significantly incremented
lipolysis in P20 cells in comparison to other compounds and in CTRL cells. On the contrary, the treatment of A7
cells with OL, CA and TO compounds significantly increased cell lipolysis. The addition of CF in differentiating
P20 pre-adipocytes significantly increased the expression of genes involved in inhibition of adipogenesis, such
as GATA2, GATA3, WNT1, WNT3A, SFRP5, and DLK1. Genes involved in promoting adipogenesis such as
CCND1, CEBPB and SREBF1 were significantly down-regulated by the treatment. The screening of bioactive
compounds for anti-adipogenic effects showed that in differentiating cells TO extract was the most effective in
inducing apoptosis and CF and DHA extracts were more efficient in inhibition of differentiation and in induction
of cell lipolysis
The Dearth of z~10 Galaxies in all HST Legacy Fields -- The Rapid Evolution of the Galaxy Population in the First 500 Myr
We present an analysis of all prime HST legacy fields spanning >800 arcmin^2
for the search of z~10 galaxy candidates and the study of their UV luminosity
function (LF). In particular, we present new z~10 candidates selected from the
full Hubble Frontier Field (HFF) dataset. Despite the addition of these new
fields, we find a low abundance of z~10 candidates with only 9 reliable sources
identified in all prime HST datasets that include the HUDF09/12, the HUDF/XDF,
all the CANDELS fields, and now the HFF survey. Based on this comprehensive
search, we find that the UV luminosity function decreases by one order of
magnitude from z~8 to z~10 at all luminosities over a four magnitude range.
This also implies a decrease of the cosmic star-formation rate density by an
order of magnitude within 170 Myr from z~8 to z~10. We show that this
accelerated evolution compared to lower redshift can entirely be explained by
the fast build-up of the dark matter halo mass function at z>8. Consequently,
the predicted UV LFs from several models of galaxy formation are in good
agreement with this observed trend, even though the measured UV LF lies at the
low end of model predictions. In particular, the number of only 9 observed
candidate galaxies is lower, by ~50%, than predicted by galaxy evolution
models. The difference is generally still consistent within the Poisson and
cosmic variance uncertainties. However, essentially all models predict larger
numbers than observed. We discuss the implications of these results in light of
the upcoming James Webb Space Telescope mission, which is poised to find much
larger samples of z~10 galaxies as well as their progenitors at less than 400
Myr after the Big Bang.Comment: 13 pages, 6 figures, minor updates to match accepted versio
Multi-wavelength surveys: object detectability an nir luminosity function of galaxies
El estudio de la evolución de la FL se extendió al rango infrarrojo, en las bandas en reposo J y H, hasta redshift 3.5. Este fue el resutlado del análisis de tres catálogos públicos desde los proyectos MUSYC, FIRES y FIREWORKS. El análisis nos permitió medir por primera vez la FL en la banda H de reposo de galaxias de campo en el rango de redshift z ¿ [1.5,3.5]; al mismo tiempo, el mayor volumen nos permitió mejorar de manera significativa la medida del extremo brillante de la FL.
Desde el punto de vista espectroscópico, desarrollamos un método novedoso para el análisis de espectros con baja razón señal-ruido, parecido a los utilizados en el análisis de datos de rayos X. El método consiste en generar espectros bi-dimensionales a partir de espectros modelos, seleccionando el que mejor reproduce los datos observados a través de minimización de ¿2. El método se aplicó en concreto al caso del GRB090423, el GRB más lejano observado hasta el momento, demostrando que se puede extraer mas información de lo que generalmente se asume desde este tipo de datos
Effects of Two Different Rhodiola rosea Extracts on Primary Human Visceral Adipocytes
Rhodiola rosea (Rro) has been reported to have various pharmacological properties, including anti-fatigue, anti-stress and anti-inflammatory activity. It is also known to improve glucose and lipid metabolism, but the effects of Rhodiola rosea on adipocyte differentiation and metabolism are not still elucidated. In this study the anti-adipogenic and lipolytic activity of two extracts of Rhodiola rosea, containing 3% salidroside (RS) or 1% salidroside and 3% rosavines (RR) on primary human visceral adipocytes was investigated. Pre-adipocytes were analyzed after 10 and 20 days of treatment during differentiation and after 7 days of treatment when they reached mature shape. The RS extract significantly induced higher apoptosis and lipolysis in comparison to control cells and to RR extract. In contrast, RR extract significantly reduced triglyceride incorporation during maturation. Differentiation of pre-adipocytes in the presence of RS and RR extracts showed a significant decrease in expression of genes involved in adipocyte function such as SLC2A4 and the adipogenic factor FGF2 and significant increase in expression of genes involved in inhibition of adipogenesis, such as GATA3, WNT3A, WNT10B. Furthermore RR extract, in contrast to RS, significantly down-regulates PPARG, the master regulator of adipogenesis and FABP4. These data support the lipolytic and anti-adipogenetic activity of two different commercial extracts of Rhodiola rosea in primary human visceral pre-adipocytes during differentiation
Extremely Small Sizes for Faint z~2-8 Galaxies in the Hubble Frontier Fields: A Key Input For Establishing their Volume Density and UV Emissivity
We provide the first observational constraints on the sizes of the faintest
galaxies lensed by the Hubble Frontier Fields (HFF) clusters. Ionizing
radiation from faint galaxies likely drives cosmic reionization, and the HFF
initiative provides a key opportunity to find such galaxies. Yet, we cannot
really assess their ionizing emissivity without a robust measurement of their
sizes, since this is key to quantifying both their prevalence and the faint-end
slope to the UV luminosity function. Here we provide the first such size
constraints with 2 new techniques. The first utilizes the fact that the
detectability of highly-magnified galaxies as a function of shear is very
dependent on a galaxy's size. Only the most compact galaxies will remain
detectable in regions of high shear (vs. a larger detectable size range for low
shear), a phenomenon we carefully quantify using simulations. Remarkably,
however, no correlation is found between the surface density of faint galaxies
and the predicted shear, using 87 faint high-magnification mu>10 z~2-8 galaxies
seen behind the first 4 HFF clusters. This can only be the case if such faint
(~-15 mag) galaxies have significantly smaller sizes than luminous galaxies. We
constrain their half-light radii to be <~30 mas (<160-240 pc). As a 2nd size
probe, we rotate and stack 26 faint high-magnification sources along the major
shear axis. Less elongation is found than even for objects with an intrinsic
half-light radius of 10 mas. Together these results indicate that extremely
faint z~2-8 galaxies have near point-source profiles in the HFF dataset
(half-light radii conservatively <30 mas and likely 5-10 mas). These results
suggest smaller completeness corrections and hence much lower volume densities
for faint z~2-8 galaxies and shallower faint-end slopes than have been derived
in many recent studies (by factors of ~2-3 and by dalpha>~0.1-0.3).Comment: 19 pages, 15 figures, 3 tables, accepted for publication in Ap
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