744 research outputs found
Galaxy clusters and groups in the ALHAMBRA Survey
We present a catalogue of 348 galaxy clusters and groups with
selected in the 2.78 ALHAMBRA Survey. The high precision of our
photometric redshifts, close to , and the wide spread of the seven
ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and
is less affected by cosmic variance than comparable samples.
The detection has been carried out with the Bayesian Cluster Finder (BCF),
whose performance has been checked in ALHAMBRA-like light-cone mock catalogues.
Great care has been taken to ensure that the observable properties of the mocks
photometry accurately correspond to those of real catalogues. From our
simulations, we expect to detect galaxy clusters and groups with both
completeness and purity down to dark matter halo masses of
for . Cluster redshifts are
expected to be recovered with precision for . We also expect
to measure cluster masses with
precision down to , masses which are
smaller than those reached by similar work.
We have compared these detections with previous optical, spectroscopic and
X-rays work, finding an excellent agreement with the rates reported from the
simulations. We have also explored the overall properties of these detections
such as the presence of a colour-magnitude relation, the evolution of the
photometric blue fraction and the clustering of these sources in the different
ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that,
for a fixed stellar mass, the environment is playing a crucial role at lower
redshifts (z0.5).Comment: Accepted for publication in MNRAS. Catalogues and figures available
online and under the following link:
http://bascaso.net46.net/ALHAMBRA_clusters.htm
The miniJPAS survey quasar selection IV: Classification and redshift estimation with SQUEzE
We present a list of quasar candidates including photometric redshift
estimates from the miniJPAS Data Release constructed using SQUEzE. This work is
based on machine-learning classification of photometric data of quasar
candidates using SQUEzE. It has the advantage that its classification procedure
can be explained to some extent, making it less of a `black box' when compared
with other classifiers. Another key advantage is that using user-defined
metrics means the user has more control over the classification. While SQUEzE
was designed for spectroscopic data, here we adapt it for multi-band
photometric data, i.e. we treat multiple narrow-band filters as very
low-resolution spectra. We train our models using specialized mocks from
Queiroz et al. (2022). We estimate our redshift precision using the normalized
median absolute deviation, applied to our test sample. Our
test sample returns an score (effectively the purity and completeness) of
0.49 for quasars down to magnitude with and 0.24 for
quasars with . For high-z quasars, this goes up to 0.9 for . We
present two catalogues of quasar candidates including redshift estimates: 301
from point-like sources and 1049 when also including extended sources. We
discuss the impact of including extended sources in our predictions (they are
not included in the mocks), as well as the impact of changing the noise model
of the mocks. We also give an explanation of SQUEzE reasoning. Our estimates
for the redshift precision using the test sample indicate a
for the entire sample, reduced to 0.81\% for
and 0.74\% for . Spectroscopic follow-up of the candidates is required
in order to confirm the validity of our findings.Comment: Accepted in A&A 24 pages, 24 figures, 7 table
The miniJPAS & J-NEP surveys: Identification and characterization of the Ly Emitter population and the Ly Luminosity Function
We present the Lyman- (Lya) Luminosity Function (LF) at ,
estimated from a sample of 67 Lya-emitter (LAE) candidates in the J-PAS
Pathfinder surveys: miniJPAS and J-NEP. These two surveys cover a total
effective area of deg with 54 Narrow Band (NB) filters across
the optical range, with typical limiting magnitudes of . This set of
NBs allows to probe Lya emission in a wide and continuous range of redshifts.
We develop a method for detecting Lya emission for the estimation of the Lya LF
using the whole J-PAS filter set. We test this method by applying it to the
miniJPAS and J-NEP data. In order to compute the corrections needed to estimate
the Lya LF and to test the performance of the candidates selection method, we
build mock catalogs. These include representative populations of Lya Emitters
at as well as their expected contaminants, namely low- galaxies
and QSOs. We show that our method is able to provide the Lya LF at the
intermediate-bright range of luminosity (). The photometric information provided
by these surveys suggests that our samples are dominated by bright,
Lya-emitting Active Galactic Nuclei. At
erg\,s, we fit our Lya LF to a power-law with slope . We
also fit a Schechter function to our data, obtaining: Log(\Phi^* /
\text{Mpc^{-3}})=-6.30^{+0.48}_{-0.70}, Log, . Overall, our
results confirm the presence of an AGN component at the bright-end of the Lya
LF. In particular, we find no significant contribution of star-forming LAEs to
the Lya LF at Log / erg\,s)>43.5. This work serves as a
proof-of-concept for the results that can be obtained with the upcoming data
releases of the J-PAS survey.Comment: 25 pages, 15 figures, submitted to A&
J-PLUS: A first glimpse at spectrophotometry of asteroids -- The MOOJa catalog
Context: The Javalambre Photometric Local Universe Survey (J-PLUS) is an
observational campaign that aims to obtain photometry in 12 ultraviolet-visible
filters (0.3-1 {\mu}m) of approximately 8 500 deg{^2} of the sky observable
from Javalambre (Teruel, Spain). Due to its characteristics and strategy of
observation, this survey will let us analyze a great number of Solar System
small bodies, with improved spectrophotometric resolution with respect to
previous large-area photometric surveys in optical wavelengths. Aims: The main
goal of this work is to present here the first catalog of magnitudes and colors
of minor bodies of the Solar System compiled using the first data release (DR1)
of the J-PLUS observational campaign: the Moving Objects Observed from
Javalambre (MOOJa) catalog. Methods: Using the compiled photometric data we
obtained very-low-resolution reflectance (photospectra) spectra of the
asteroids. We first used a {\sigma}-clipping algorithm in order to remove
outliers and clean the data. We then devised a method to select the optimal
solar colors in the J-PLUS photometric system. These solar colors were computed
using two different approaches: on one hand, we used different spectra of the
Sun, convolved with the filter transmissions of the J-PLUS system, and on the
other, we selected a group of solar-type stars in the J-PLUS DR1, according to
their computed stellar parameters. Finally, we used the solar colors to obtain
the reflectance spectra of the asteroids. Results: We present photometric data
in the J-PLUS filters for a total of 3 122 minor bodies (3 666 before outlier
removal), and we discuss the main issues of the data, as well as some
guidelines to solve the
Correction: C-MET receptor as potential biomarker and target molecule for malignant testicular germ cell tumors
This article has been corrected: The correct author name is given below: Mariano Bizzarri
International multicenter observational study on assessment of ventilatory management during general anaesthesia for robotic surgery and its effects on postoperative pulmonary complication (AVATaR) : study protocol and statistical analysis plan
Introduction: Robotic-assisted surgery (RAS) has emerged as an alternative minimally invasive surgical option. Despite its growing applicability, the frequent need for pneumoperitoneum and Trendelenburg position could significantly affect respiratory mechanics during RAS. AVATaR is an international multicenter observational study aiming to assess the incidence of postoperative pulmonary complications (PPC), to characterise current practices of mechanical ventilation (MV) and to evaluate a possible association between ventilatory parameters and PPC in patients undergoing RAS.
Methods and analysis: AVATaR is an observational study of surgical patients undergoing MV for general anaesthesia for RAS. The primary outcome is the incidence of PPC during the first five postoperative days. Secondary outcomes include practice of MV, effect of surgical positioning on MV, effect of MV on clinical outcome and intraoperative complications.
Ethics and dissemination: This study was approved by the Institutional Review Board of the Hospital Israelita Albert Einstein. The study results will be published in peer-reviewed journals and disseminated at international conferences.
Trial registration number: NCT02989415; Pre-results
Long-term home ventilation of children in Italy: A national survey.
BACKGROUND:
Improved technology, as well as professional and parental awareness, enable many ventilator-dependent children to live at home. However, the profile of this growing population, the quality and adequacy of home care, and patients' needs still require thorough assessment.
OBJECTIVES:
To define the characteristics of Italian children receiving long-term home mechanical ventilation (HMV) in Italy.
METHODS:
A detailed questionnaire was sent to 302 National Health Service hospitals potentially involved in the care of HVM in children (aged <17 years). Information was collected on patient characteristics, type of ventilation, and home respiratory care.
RESULTS:
A total of 362 HMV children was identified. The prevalence was 4.2 per 100,000 (95% CI: 3.8-4.6), median age was 8 years (interquartile range 4-14), median age at starting mechanical ventilation was 4 years (1-11), and 56% were male. The most frequent diagnostic categories were neuromuscular disorders (49%), lung and upper respiratory tract diseases (18%), hypoxic (ischemic) encephalopathy (13%), and abnormal ventilation control (12%). Medical professionals with nurses (for 62% of children) and physiotherapists (20%) participated in the patients' discharge from hospital, though parents were the primary care giver, and in 47% of cases, the sole care giver. Invasive ventilation was used in 41% and was significantly related to young age, southern regional residence, longer time spent under mechanical ventilation, neuromuscular disorders, or hypoxic (ischemic) encephalopathy.
CONCLUSIONS:
Care and technical assistance of long-term HMV children need assessment, planning, and resources. A wide variability in pattern of HMV was found throughout Italy. An Italian national ventilation program, as well as a national registry, could be useful in improving the care of these often critically ill children
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
J-PAS: forecasts on dark energy and modified gravity theories
The next generation of galaxy surveys will allow us to test one of the most fundamental assumptions of the standard cosmology, i.e. that gravity is governed by the general theory of relativity (GR). In this paper, we investigate the ability of the Javalambre Physics of the AcceleratingUniverseAstrophysical Survey (J-PAS) to constrainGR and its extensions. Based on the J-PAS information on clustering and gravitational lensing, we perform a Fisher matrix forecast on the effective Newton constant, mu, and the gravitational slip parameter, eta, whose deviations from unity would indicate a breakdown of GR. Similar analysis is also performed for the DESI and Euclid surveys and compared to J-PAS with two configurations providing different areas, namely an initial expectation with 4000 deg(2) and the future best case scenario with 8500 deg(2). We show that J-PAS will be able to measure the parameters mu and eta at a sensitivity of 2-7 per cent, and will provide the best constraints in the interval z = 0.3-0.6, thanks to the large number of ELGs detectable in that redshift range. We also discuss the constraining power of J-PAS for dark energy models with a time-dependent equation-of-state parameter of the type w(a) = w(0) + w(a)(1 - a), obtaining Delta w(0) = 0.058 and Delta w(a) = 0.24 for the absolute errors of the dark energy parameters.© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyWe are thankful to our colleagues of J-PAS Theory Working Group for useful discussions and to Ricardo Landim for his comments. MAR and ALM acknowledge support from MINECO (Spain) project FIS2016-78859-P (AEI/FEDER, UE), Red Consolider MultiDark FPA2017-90566-REDC, and UCM pre-doctoral grant. JSA acknowledges support from FAPERJ grant no. E-26/203.024/2017; CNPq grant no. 310790/2014-0 and 400471/2014-0; and the Financiadora de Estudos e Projetos -FINEP grants REF. 1217/13-01.13.0279.00 and REF0859/10-01.10.0663.00. SC acknowledges support from CNPq grant nos 307467/2017-1 and 420641/2018-1.
This paper has gone through internal review by the J-PAS collaboration. Funding for the J-PAS Project has been provided by the Governments of Espana and Aragon through the Fondo de Inversion de Teruel, European FEDER funding, the MINECO projects AYA2015-66211-C2-1- P, AYA2015-66211-C2-2, and AYA2012-30789; the Brazilian agencies FINEP, FAPESP, FAPERJ and by the National Observatory of Brazil.Peer reviewe
Are we ready to track climate-driven shifts in marine species across international boundaries? - A global survey of scientific bottom trawl data
Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. Given that the primary purpose of surveys is to provide independent data to inform stock assessment of commercially important populations, we further highlight that single surveys do not cover the full range of the main commercial demersal fish species. An average of 18 surveys is needed to cover at least 50% of species ranges, demonstrating the importance of combining multiple surveys to evaluate species range shifts. We assess the potential for combining surveys to track transboundary species redistributions and show that differences in sampling schemes and inconsistency in sampling can be overcome with spatio-temporal modeling to follow species density redistributions. In light of our global assessment, we establish a framework for improving the management and conservation of transboundary and migrating marine demersal species. We provide directions to improve data availability and encourage countries to share survey data, to assess species vulnerabilities, and to support management adaptation in a time of climate-driven ocean changes.En prensa6,86
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