563 research outputs found
Undecidability as solution to the problem of measurement: fundamental criterion for the production of events
In recent papers we put forth a new interpretation of quantum mechanics,
colloquially known as ``the Montevideo interpretation''. This interpretation is
based on taking into account fundamental limits that gravity imposes on the
measurement process. As a consequence one has that situations develop where a
reduction process is undecidable from an evolution operator. When such a
situation is achieved, an event has taken place. In this paper we sharpen the
definition of when and how events occur, more precisely we give sufficient
conditions for the occurrence of events. We probe the new definition in an
example. In particular we show that the concept of undecidability used is not
``FAPP'' (for all practical purposes), but fundamental.Comment: 10 pages, contributed to the Castagnino Festschrif
Lyman break and UV-selected galaxies at I. Stellar populations from ALHAMBRA survey
We take advantage of the exceptional photometric coverage provided by the
combination of GALEX data in the UV and the ALHAMBRA survey in the optical and
near-IR to analyze the physical properties of a sample of 1225 GALEX-selected
Lyman break galaxies (LBGs) at located in the
COSMOS field. This is the largest sample of LBGs studied at that redshift range
so far. According to a spectral energy distribution (SED) fitting with
synthetic stellar population templates, we find that LBGs at are
mostly young galaxies with a median age of 341 Myr and have intermediate dust
attenuation, . Due to their selection criterion,
LBGs at are UV-bright galaxies and have high dust-corrected total
SFR, with a median value of 16.9 . Their median stellar
mass is . We obtain that the
dust-corrected total SFR of LBGs increases with stellar mass and the specific
SFR is lower for more massive galaxies. Only 2% of the galaxies selected
through the Lyman break criterion have an AGN nature. LBGs at are
mostly located over the blue cloud of the color-magnitude diagram of galaxies
at their redshift, with only the oldest and/or the dustiest deviating towards
the green valley and red sequence. Morphologically, 69% of LBGs are disk-like
galaxies, with the fraction of interacting, compact, or irregular systems being
much lower, below 12%. LBGs have a median effective radius of 2.5 kpc and
bigger galaxies have higher total SFR and stellar mass. Comparing to their
high-redshift analogues, we find evidence that LBGs at lower redshifts are
bigger, redder in the UV continuum, and have a major presence of older stellar
populations in their SEDs. However, we do not find significant difference in
the distributions of stellar mass or dust attenuation.Comment: Accepted for publication in MNRA
Galaxy classification: deep learning on the OTELO and COSMOS databases
Context. The accurate classification of hundreds of thousands of galaxies
observed in modern deep surveys is imperative if we want to understand the
universe and its evolution. Aims. Here, we report the use of machine learning
techniques to classify early- and late-type galaxies in the OTELO and COSMOS
databases using optical and infrared photometry and available shape parameters:
either the Sersic index or the concentration index. Methods. We used three
classification methods for the OTELO database: 1) u-r color separation , 2)
linear discriminant analysis using u-r and a shape parameter classification,
and 3) a deep neural network using the r magnitude, several colors, and a shape
parameter. We analyzed the performance of each method by sample bootstrapping
and tested the performance of our neural network architecture using COSMOS
data. Results. The accuracy achieved by the deep neural network is greater than
that of the other classification methods, and it can also operate with missing
data. Our neural network architecture is able to classify both OTELO and COSMOS
datasets regardless of small differences in the photometric bands used in each
catalog. Conclusions. In this study we show that the use of deep neural
networks is a robust method to mine the cataloged dataComment: 20 pages, 10 tables, 14 figures, Astronomy and Astrophysics (in
press
Newborn screening for medium-chain acyl-CoA dehydrogenase deficiency: regional experience and high incidence of carnitine deficiency
Background
Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common inherited defect in the mitochondrial fatty acid oxidation pathway, resulting in significant morbidity and mortality in undiagnosed patients.
Newborn screening (NBS) has considerably improved MCADD outcome, but the risk of complication remains in some patients. The aim of this study was to evaluate the relationship between genotype, biochemical parameters and clinical data at diagnosis and during follow-up, in order to optimize monitoring of these patients.
Methods
We carried out a multicenter study in southwest Europe, of MCADD patients detected by NBS. Evaluated NBS data included free carnitine (C0) and the acylcarnitines C8, C10, C10:1 together with C8/C2 and C8/C10 ratios, clinical presentation parameters and genotype, in 45 patients. Follow-up data included C0 levels, duration of carnitine supplementation and occurrence of metabolic crises.
Results
C8/C2 ratio and C8 were the most accurate biomarkers of MCADD in NBS. We found a high number of patients homozygous for the prevalent c.985A > G mutation (75%). Moreover, in these patients C8, C8/C10 and C8/C2 were higher than in patients with other genotypes, while median value of C0 was significantly lower (23 μmol/L vs 36 μmol/L).
The average follow-up period was 43 months. To keep carnitine levels within the normal range, carnitine supplementation was required in 82% of patients, and for a longer period in patients homozygotes for the c.985A>G mutation than in patients with other genotypes (average 31 vs 18 months). Even with treatment, median C0 levels remained lower in homozygous patients than in those with other genotypes (14 μmol/L vs 22 μmol/L).
Two patients died and another three suffered a metabolic crisis, all of whom were homozygous for the c.985 A>G mutation.
Conclusions
Our data show a direct association between homozygosity for c.985A>G and lower carnitine values at diagnosis, and a higher dose of carnitine supplementation for maintenance within the normal range. This study contributes to a better understanding of the relationship between genotype and phenotype in newborn patients with MCADD detected through screening which could be useful in improving follow-up strategies and clinical outcome
The OTELO survey. A case study of [O III]4959,5007 emitters at <z> = 0.83
The OTELO survey is a very deep, blind exploration of a selected region of
the Extended Groth Strip and is designed for finding emission-line sources
(ELSs). The survey design, observations, data reduction, astrometry, and
photometry, as well as the correlation with ancillary data used to obtain a
final catalogue, including photo-z estimates and a preliminary selection of
ELS, were described in a previous contribution. Here, we aim to determine the
main properties and luminosity function (LF) of the [O III] ELS sample of OTELO
as a scientific demonstration of its capabilities, advantages, and
complementarity with respect to other surveys. The selection and analysis
procedures of ELS candidates obtained using tunable filter (TF) pseudo-spectra
are described. We performed simulations in the parameter space of the survey to
obtain emission-line detection probabilities. Relevant characteristics of [O
III] emitters and the LF([O III]), including the main selection biases and
uncertainties, are presented. A total of 184 sources were confirmed as [O III]
emitters at a mean redshift z=0.83. The minimum detectable line flux and
equivalent width (EW) in this ELS sample are 5 10 erg
s cm and 6 \AA, respectively. We are able to constrain the
faint-end slope () of the observed LF([O III]) at
z=0.83. This LF reaches values that are approximately ten times lower than
those from other surveys. The vast majority (84\%) of the morphologically
classified [O III] ELSs are disc-like sources, and 87\% of this sample is
comprised of galaxies with stellar masses of M 10
M.Comment: v1: 16 pages, 6 figures. Accepted in Astronomy \& Astrophysics. v2:
Author added in metadat
Physical properties of Lyman-alpha emitters at from UV-to-FIR measurements
The analysis of the physical properties of low-redshift Ly emitters
(LAEs) can provide clues in the study of their high-redshift analogues. At , LAEs are bright enough to be detected over almost the entire
electromagnetic spectrum and it is possible to carry out a more precise and
complete study than at higher redshifts. In this study, we examine the UV and
IR emission, dust attenuation, SFR and morphology of a sample of 23
GALEX-discovered star-forming (SF) LAEs at with direct UV (GALEX),
optical (ACS) and FIR (PACS and MIPS) data. Using the same UV and IR limiting
luminosities, we find that LAEs at tend to be less dusty, have
slightly higher total SFRs, have bluer UV continuum slopes, and are much
smaller than other galaxies that do not exhibit Ly emission in their
spectrum (non-LAEs). These results suggest that at Ly
photons tend to escape from small galaxies with low dust attenuation. Regarding
their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and
morphology represent the most noticeable difference between LAEs and non-LAEs
at . Furthermore, the comparison of our results with those obtained
at higher redshifts indicates that either the Ly technique picks up
different kind of galaxies at different redshifts or that the physical
properties of LAEs are evolving with redshift.Comment: Accepted for publication in Ap
PACS-Herschel FIR detections of Lyman-alpha emitters at 2.0<z<3.5
In this work we analyze the physical properties of a sample of 56
spectroscopically selected star-forming (SF) Ly emitting galaxies at
2.0z3.5 using both a spectral energy distribution (SED)
fitting procedure from rest-frame UV to mid-IR and direct 160m
observations taken with the Photodetector Array Camera & Spectrometer (PACS)
instrument onboard \emph{Herschel Space Observatory}. We define LAEs as those
Ly emitting galaxies whose rest-frame Ly equivalent widths
(Ly EW) are above 20\AA, the typical threshold in
narrow-band searches. Ly emitting galaxies with Ly
EW are called non-LAEs. As a result of an individual SED fitting
for each object, we find that the studied sample of LAEs contains galaxies with
ages mostly below 100Myr and a wide variety of dust attenuations, SFRs, and
stellar masses. The heterogeneity in the physical properties is also seen in
the morphology, ranging from bulge-like galaxies to highly clumpy systems. In
this way, we find that LAEs at 2.0z3.5 are very diverse,
and do not have a bimodal nature, as suggested in previous works. Furthermore,
the main difference between LAEs and non-LAEs is their dust attenuation,
because LAEs are not as dusty as non-LAEs. On the FIR side, four galaxies of
the sample (two LAEs and two non-LAEs) have PACS-FIR counterparts. Their total
IR luminosity place all of them in the ULIRG regime and are all dusty objects,
with A4mag. This is an indication from direct FIR
measurements that dust and Ly emission are not mutually exclusive. This
population of red and dusty LAEs is not seen at z0.3, suggesting an
evolution with redshift of the IR nature of galaxies selected via their
Ly emission.Comment: Accepted for publication in A&
Un nuevo concepto de la gastronomía desde la bioeconomía y la actividad académica
El proyecto “Ciencia y arte en gastronomía: botánica gastronómica y
gastronomía molecular” se está desarrollando con el objetivo de establecer y
organizar el intercambio de conocimientos y negocio en este ámbito. Con este
objetivo se pretende aunar el conocimiento científico con la salud y el bienestar
social desde la perspectiva bioeconómica promoviendo la creación de riqueza y
trabajo. El proyecto forma parte de los cursos especializados que la Universidad
Complutense de Madrid oferta con el animo de incrementar el conocimiento y
desarrollar competencias personales y profesionales. El programa responde a la
demanda social proporcionando una formación con inmediata proyección
profesional mediante el establecimiento de un nexo directo entre la actividad
académica y la realidad social.Universidad de Sevilla. Cristalografía, Mineralogía y Química Agrícola
The project "Science and art in gastronomy: gastronomic botany and
molecular gastronomy" is being developed with the aim to establish and organize
the exchange of knowledge and business in this area. In this way we are working
to join the scientific knowledge to the health and the social well-being, without
losing the current perspective from the bioeconomy which look forward the generation of wealth and work. The project belongs to specialized courses
offered by The Complutense University of Madrid which aim is to update the
knowledge and develop personal and professional competitions. These programs
answer to a social demand on providing formation with professional immediate
projection establishing a direct relation between the academic activity and the
social reality
- …
