3 research outputs found
Multiwavelength analysis of brightness variations of 3C~279: Probing the relativistic jet structure and its evolution
We studied the correlation between brightness and polarization variations in
3C~279 at different wavelengths, over time intervals long enough to cover the
time lags due to opacity effects. We used these correlations together with VLBI
images to constrain the radio and high energy source position.We made 7 mm
radio continuum and -band polarimetric observations of 3C~279 between 2009
and 2014. The radio observations were performed at the Itapetinga Radio
Observatory, while the polarimetric data were obtained at Pico dos Dias
Observatory, both in Brazil. We compared our observations with the -ray
Fermi/LAT and -band SMARTS light curves. We found a good correlation between
7~mm and -band light curves, with a delay of days in radio, but
no correlation with the rays. However, a group of several -ray
flares in April 2011 could be associated with the start of the 7 mm strong
activity observed at the end of 2011.We also detected an increase in -band
polarization degree and rotation of the polarization angle simultaneous with
these flares. Contemporaneous VLBI images at the same radio frequency show two
new strong components close to the core, ejected in directions very different
from that of the jet.The good correlation between radio and -band
variability suggests that their origin is synchrotron radiation. The lack of
correlation with -rays produced by the Inverse Compton process on some
occasions could be due to the lack of low energy photons in the jet direction
or to absorption of the high energy photons by the broad line region clouds.
The variability of the polarization parameters during flares can be easily
explained by the combination of the jet polarization parameters and those of
newly formed jet components.Comment: 11 pages, 6 figures, 2 tables. Accepted by A&
A panchromatic spatially resolved study of the inner 500pc of NGC1052 -- II: Gas excitation and kinematics
We map the optical and near-infrared (NIR) emission-line flux distributions
and kinematics of the inner 320535pc of the elliptical galaxy
NGC1052. The integral field spectra were obtained with the Gemini Telescope
using the GMOS-IFU and NIFS instruments, with angular resolutions of 0''88 and
0''1 in the optical and NIR, respectively. We detect five kinematic components:
(1 and 2) Two spatially unresolved components, being a broad line region
visible in H, with a FWHM of 3200km s and an
intermediate-broad component seen in the [OIII]4959,5007
doublet; (3) an extended intermediate-width component with 280<FWHM<450km
s and centroid velocities up to 400km s, which dominates the flux
in our data, attributed either to a bipolar outflow related to the jets,
rotation in an eccentric disc or a combination of a disc and large-scale gas
bubbles; (4 and 5) two narrow (FWHM<150km s) components, one visible in
[OIII], and one visible in the other emission lines, extending beyond the
field-of-view of our data, which is attributed to large-scale shocks. Our
results suggest that the ionization within the observed field of view cannot be
explained by a single mechanism, with photoionization being the dominant
mechanism in the nucleus with a combination of shocks and photoionization
responsible for the extended ionization.Comment: Accepted at MNRAS. 17 pages, 17 figure
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030