The sub-mJy radio population is a mixture of active systems, that is star-forming galaxies (SFGs) and active galactic nuclei (AGNs). We study a sample of 883 radio sources detected at 1.4 GHz in a ...deep Very Large Array survey of the Extended Chandra Deep Field-South that reaches a best rms sensitivity of 6 μJy. We have used a simple scheme to disentangle SFGs, radio-quiet (RQ), and radio-loud (RL) AGNs based on the combination of radio data with Chandra X-ray data and mid-infrared observations from Spitzer. We find that at flux densities between about 30 and 100 μJy, the radio population is dominated by SFGs (~60 per cent) and that RQ AGNs become increasingly important over RL ones below 100 μJy. We also compare the host galaxy properties of the three classes in terms of morphology, optical colours and stellar masses. Our results show that both SFG and RQ AGN host galaxies have blue colours and late-type morphology while RL AGNs tend to be hosted by massive red galaxies with early-type morphology. This supports the hypothesis that radio emission in SFGs and RQ AGNs mainly comes from the same physical process: star formation in the host galaxy. PUBLICATION ABSTRACT
Abstract
Similarly to the cosmic star formation history, the black hole accretion rate density of the Universe peaked at 1 < z < 3. This cosmic epoch is hence best suited for investigating the ...effects of radiative feedback from active galactic nucleus (AGN). Observational efforts are under way to quantify the impact of the AGN feedback, if any, on their host galaxies. Here, we present a study of the molecular gas content of AGN hosts at z ∼ 1.5 using CO2−1 line emission observed with Atacama Large Millimeter/sub-mm Array (ALMA) for a sample of 10 AGNs. We compare this with a sample of galaxies without an AGN matched in redshift, stellar mass and star formation rate. We detect CO in three AGNs with L
CO ∼ 6.3–25.1 × 109 L⊙, which translates to a molecular hydrogen gas mass of 2.5–10 × 1010 M⊙ assuming conventional conversion factor of αCO ∼ 3.6. Our results indicate a >99 per cent probability of lower depletion time-scales and lower molecular gas fractions in AGN hosts with respect to the non-AGN comparison sample. We discuss the implications of these observations on the impact that AGN feedback may have on star formation efficiency of z >1 galaxies.
We investigate the star formation properties of ∼800 sources detected in one of the deepest radio surveys at 1.4 GHz. Our sample spans a wide redshift range (∼0.1–4) and about four orders of ...magnitude in star formation rate (SFR). It includes both star-forming galaxies (SFGs) and active galactic nuclei (AGNs), further divided into radio-quiet (RQ) and radio-loud objects. We compare the SFR derived from the far-infrared luminosity, as traced by Herschel, with the SFR computed from their radio emission. We find that the radio power is a good SFR tracer not only for pure SFGs but also in the host galaxies of RQ AGNs, with no significant deviation with redshift or specific SFR. Moreover, we quantify the contribution of the starburst activity in the SFG population and the occurrence of AGNs in sources with different level of star formation. Finally, we discuss the possibility of using deep radio survey as a tool to study the cosmic star formation history.
Radio-faint AGN: a tale of two populations Padovani, P; Bonzini, M; Kellermann, K. I ...
Monthly Notices of the Royal Astronomical Society,
09/2015, Letnik:
452, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We study the Extended Chandra
Deep Field-South Very Large Array sample, which reaches a flux density limit at 1.4 GHz of 32.5 μJy at the field centre and redshift ∼4, and covers ∼0.3 deg2. Number ...counts are presented for the whole sample while the evolutionary properties and luminosity functions are derived for active galactic nuclei (AGN). The faint radio sky contains two totally distinct AGN populations, characterized by very different evolutions, luminosity functions, and Eddington ratios: radio-quiet (RQ)/radiative-mode and radio-loud (RL)/jet-mode AGN. The radio power of RQ AGN evolves
$\mathrel {{\rlap{{\lower4pt{\sim }}}{\propto }}}(1+z)^{2.5}$
, similarly to star-forming galaxies, while the number density of RL ones has a peak at z ∼ 0.5 and then declines at higher redshifts. The number density of radio-selected RQ AGN is consistent with that of X-ray selected AGN, which shows that we are sampling the same population. The unbiased fraction of radiative-mode RL AGN, derived from our own and previously published data, is a strong function of radio power, decreasing from ∼0.5 at P
1.4 GHz ∼ 1024 W Hz−1 to ∼0.04 at P
1.4 GHz ∼ 1022 W Hz−1. Thanks to our enlarged sample, which now includes ∼700 radio sources, we also confirm and strengthen our previous results on the source population of the faint radio sky: star-forming galaxies start to dominate the radio sky only below ∼0.1 mJy, which is also where RQ AGN overtake RL ones.
The COVID-19 pandemic is currently a severe challenge for healthcare workers, with a considerable impact on their mental health. In order to focus preventive and rehabilitation measures it's ...fundamental to identify risk factors of such psychological impairment. We designed an observational longitudinal study to systematically examine the psychological wellbeing of all employees in a large University Hospital in Italy, using validated psychometric scales in the context of the occupational physician's health surveillance, in collaboration with Psychiatric Unit.
The study started after ethical approval in August 2020. For each worker, the psychological wellbeing is screened in two steps. The first level questionnaire collects sociodemographic characteristics, personal and occupational COVID-19 exposure, worries and concerns about COVID-19, general psychological discomfort (GHQ-12), post-traumatic stress symptoms (IES-R) and anxiety (GAD-7). Workers who score above the cut-off in at least one scale are further investigated by the second level questionnaire composed by PHQ-9, DES-II and SCL-90. If second level shows psychological impairments, we offer individual specialist treatment (third level). We plan to follow-up all subjects to monitor symptoms and possible chronicization; we aim to investigate potential risk factors through univariate analysis and multivariate logistic regressions.
Preliminary results refer to a sample of 550 workers who completed the multi-step evaluation from August to December 2020, before vaccination campaign started. The participation rate was 90%. At first level screening, 39% of the subjects expressed general psychological discomfort (GHQ-12), 22% post-traumatic stress symptoms (IES-R), and 21% symptoms of anxiety (GAD-7). Women, nurses, younger workers, subjects with COVID-19 working exposure and with an infected family member showed significantly higher psychological impairment compared to colleagues. After the second level screening, 12% and 7% of all workers showed, respectively, depressive and dissociative symptoms; scorings were significantly associated with gender and occupational role. We are currently extending sample size and evaluating subjects over a period of further 12 months.
The possibility to perform a systematic follow-up of psychological wellbeing of all hospital workers, directly or indirectly exposed to pandemic consequences, constitutes a unique condition to detect individual, occupational, and non-occupational risk factors for psychological impairment in situations of prolonged stress, as well as variables associated with symptoms chronicization.
Computed tomographic pulmonary angiography (CTPA) has simplified the diagnostic approach to patients with suspected pulmonary embolism (PE). However, PE diagnosis is still probabilistic and CTPA ...should be used with caution in some patient groups, such as patients with severe renal insufficiency and pregnant women. Among alternative imaging tests, lung ultrasound is the most promising technique. We aimed to systematically assess the diagnostic accuracy of lung ultrasound for PE diagnosis.
Studies evaluating the diagnostic accuracy of lung ultrasound for the diagnosis of PE were systematically searched for in the MEDLINE and EMBASE databases (up to June 2012). The QUADAS-2 tool was used for the quality assessment of the primary studies. A bivariate random-effects regression approach was used for summary estimates of both sensitivity and specificity.
Ten studies, for a total of 887 patients, were included. A composite reference test was used in six studies, with single-row detector CTPA as the principal imaging test in four studies. Overall, seven studies used a proper reference test. Lung ultrasound bivariate weighted mean sensitivity was 87.0% (95% confidence interval CI 79.5, 92.0%), whereas bivariate weighted mean specificity was 81.8% (95% CI 71.0, 89.3%).
Our findings suggest that lung ultrasound may be a useful diagnostic tool in the management of patients with suspected PE. However, several methodological drawbacks of the primary studies limit any definite conclusion. Further well-designed accuracy studies are necessary before planning diagnostic management studies, in particular in those with a contraindication for CTPA.
Quantitative measurement of circulating D-dimer, a product of fibrin degradation, has been shown to be a very useful diagnostic tool in the management of patients with suspected deep vein thrombosis ...and/or pulmonary embolism. Whether D-dimer can play a similar role in the diagnostic approach to patients with suspected cerebral vein thrombosis (CVT) remains controversial.
Studies evaluating the diagnostic accuracy of the D-dimer test in the diagnosis of CVT were systematically searched for in the MEDLINE and EMBASE databases (up to July 2011). Weighted mean sensitivity and specificity with 95% confidence intervals (CIs) were calculated with a bivariate random-effects regression approach.
Fourteen studies, for a total of 1134 patients, were included. D-dimer accuracy was good, with a resulting weighted mean sensitivity of 93.9% (95% CI 87.5-97.1) and weighted mean specificity of 89.7% (95% CI 86.5-92.2), calculated with a bivariate approach. Potential risk factors for false-negative D-dimer results included isolated headache, longer duration of symptoms, and limited sinus involvement.
Our findings suggest that D-dimer may be a useful diagnostic tool in the management of patients with suspected CVT. Future prospective studies are warranted to confirm our preliminary findings.
Please cite this paper as: Bonzini M, Palmer K, Coggon D, Carugno M, Cromi A, Ferrario M. Shift work and pregnancy outcomes: a systematic review with meta‐analysis of currently available ...epidemiological studies. BJOG 2011;118:1429–1437.
Background Varying work schedules are suspected of increasing risks to pregnant women and to fetal wellbeing. In particular, maternal hormonal disturbance arising from sleep deprivation or circadian rhythm disruption might impair fetal growth or lead to complications of pregnancy. Two independent meta‐analyses (from 2000 to 2007) reported a small adverse effect of shift work on the risk of preterm delivery (PTD). However, these reviews were based on few high‐quality studies.
Objectives To provide an updated review of the associations of shift work with PTD, low birthweight (LBW), small‐for‐gestational‐age (SGA) infants and pre‐eclampsia.
Search strategy and selection criteria We conducted a systematic search of MEDLINE using combinations of keywords and MeSH terms.
Data collection and analysis For each relevant paper we ed standard details, used to summarise design features and rate methodological quality. We calculated pooled estimates of relative risk (RR) in random‐effect meta‐analyses.
Main results We retrieved 23 relevant studies. The pooled estimate of RR for PTD was 1.16 (95% CI 1.00–1.33, 16 studies), but when five reports of poorer methodological quality were excluded, the estimated RR decreased to 1.03 (95% CI 0.93–1.14). We also observed increased RRs for LBW (RR 1.27, 95% CI 0.93–1.74) and for SGA (RR 1.12, 95% CI 1.03–1.22), which varied little by study quality. Little evidence was found on pre‐eclampsia.
Conclusions These findings suggest that overall, any risk of PTD, LBW, or SGA arising from shift work in pregnancy is small.
We study a sample of 883 sources detected in a deep Very Large Array survey at 1.4 GHz in the Extended Chandra Deep Field South. This paper focuses on the identification of their optical and infrared ...(IR) counterparts. We use a likelihood-ratio technique that is particularly useful when dealing with deep optical images to minimize the number of spurious associations. We find a reliable counterpart for 95% of our radio sources. Most of the counterparts (74%) are detected at optical wavelengths, but there is a significant fraction (21%) that are only detectable in the IR. Combining newly acquired optical spectra with data from the literature, we are able to assign a redshift to 81% of the identified radio sources (37% spectroscopic). We also investigate the X-ray properties of the radio sources using the Chandra 4 Ms and 250 ks observations. In particular, we use a stacking technique to derive the average properties of radio objects undetected in the Chandra images. The results of our analysis are collected in a new catalog containing the position of the optical/IR counterpart, the redshift information, and the X-ray fluxes. It is the deepest multi-wavelength catalog of radio sources, which will be used for future study of this galaxy population.
Particulate matter (PM) exposure has been linked to increased risk of cardiovascular disease, possibly resulting from hypercoagulability and thrombosis. Lung and systemic inflammation resulting from ...PM inhalation may activate blood coagulation, but mechanisms for PM-related hypercoagulability are still largely unknown.
To identify coagulation mechanisms activated by PM in a population with well-characterized exposure.
We measured prothrombin time (PT), activated partial thromboplastin time, endogenous thrombin potentials (ETPs) with/without exogenous triggers and with/without soluble thrombomodulin, tissue-type plasminogen activator (t-PA) antigen, D-dimer and C-reactive protein (CRP) in 37 workers in a steel production plant with well-characterized exposure to PM with aerodynamic diameter of < 1 mum (PM(1)) and coarse PM (PM(10) - PM(1)). Blood samples were collected from each subject on the first (baseline) and last (postexposure) day of a 4-day work week. We analyzed differences between baseline and postexposure levels using a paired Student's t-test. We fitted multivariate mixed-regression models to estimate the associations of interquartile range PM(1) and coarse PM exposure with parameter levels.
None of the parameters showed any significant changes from baseline in postexposure samples. However, exposure levels were associated with shorter PT (betaPM(1) = -0.33 s, P = 0.08; betaPM(coarse) = - 0.33 s, P = 0.01), and higher ETP without exogenous triggers and with thrombomodulin (betaPM(1) = + 99 nm min, P = 0.02; betaPM(coarse) = + 66 nm min, P = 0.05), t-PA (betaPM(1) = + 0.72 ng mL(-1), P = 0.01; betaPM(coarse) = + 0.88 ng mL(-1), P = 0.04), and CRP (betaPM(1) = + 0.59 mg L(-1), P = 0.03; betaPM(coarse) = + 0.48 mg L(-1), P = 0.01).
PM exposure did not show any short-term effect within the week of the study. The association of PM exposure with PT, ETP and CRP provides some evidence of long-term effects on inflammation and coagulation.
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