ABSTRACT
We report the detection of a bright fast radio burst, FRB 191108, with Apertif on the Westerbork Synthesis Radio Telescope. The interferometer allows us to localize the FRB to a narrow 5 ...arcsec × 7 arcmin ellipse by employing both multibeam information within the Apertif phased-array feed beam pattern, and across different tied-array beams. The resulting sightline passes close to Local Group galaxy M33, with an impact parameter of only 18 kpc with respect to the core. It also traverses the much larger circumgalactic medium (CGM) of M31, the Andromeda Galaxy. We find that the shared plasma of the Local Group galaxies could contribute ∼10 per cent of its dispersion measure of 588 pc cm−3. FRB 191108 has a Faraday rotation measure (RM) of +474 $\pm \, 3$ rad m−2, which is too large to be explained by either the Milky Way or the intergalactic medium. Based on the more moderate RMs of other extragalactic sources that traverse the halo of M33, we conclude that the dense magnetized plasma resides in the host galaxy. The FRB exhibits frequency structure on two scales, one that is consistent with quenched Galactic scintillation and broader spectral structure with Δν ≈ 40 MHz. If the latter is due to scattering in the shared M33/M31 CGM, our results constrain the Local Group plasma environment. We found no accompanying persistent radio sources in the Apertif imaging survey data.
Context.
Detection of the electromagnetic emission from coalescing binary neutron stars (BNS) is important for understanding the merger and afterglow.
Aims.
We present a search for a radio ...counterpart to the gravitational-wave (GW) source GW190425, a BNS merger, using Apertif on the Westerbork Synthesis Radio Telescope (WSRT).
Methods.
We observed a field of high probability in the associated localisation region for three epochs at Δ
T
= 68, 90, 109 d post merger. We identified all sources that exhibit flux variations consistent with the expected afterglow emission of GW190425. We also looked for possible transients. These are sources that are only present in one epoch. In addition, we quantified our ability to search for radio afterglows in the fourth and future observing runs of the GW detector network using Monte Carlo simulations.
Results.
We found 25 afterglow candidates based on their variability. None of these could be associated with a possible host galaxy at the luminosity distance of GW190425. We also found 55 transient afterglow candidates that were only detected in one epoch. All of these candidates turned out to be image artefacts. In the fourth observing run, we predict that up to three afterglows will be detectable by Apertif.
Conclusions.
While we did not find a source related to the afterglow emission of GW190425, the search validates our methods for future searches of radio afterglows.
Objectives. Published reports were reviewed to evaluate the characteristics of peripartal management and the late pregnancy outcome in women with pulmonary vascular disease (PVD).
Background. ...Pulmonary hypertension poses one of the highest risks for maternal mortality, but actual data on the maternal and neonatal prognosis in this group are lacking.
Methods. Reports published from 1978 through 1996 of Eisenmenger’s syndrome (n = 73), primary pulmonary hypertension (PPH) (n = 27) and secondary vascular pulmonary hypertension (SVPH) (n = 25) complicating late pregnancy were included and analyzed using logistic regression analysis.
Results. Maternal mortality was 36% in Eisenmenger’s syndrome, 30% in PPH and 56% (p < 0.08 vs. other two groups) in SVPH. Except for three prepartal deaths due to Eisenmenger’s syndrome, all fatalities occurred within 35 days after delivery. Neonatal survival ranging from 87% to 89% was similar in the three groups. Previous pregnancies, timing of the diagnosis and hospital admission, operative delivery and diastolic pulmonary artery pressure were significant univariate (p < 0.05) maternal risk factors. Late diagnosis (p = 0.002, odds ratio 5.4) and late hospital admission (p = 0.01, odds ratio 1.1 per week of pregnancy) were independent predictive risk factors of maternal mortality.
Conclusions. In the last two decades maternal mortality was comparable in patients with Eisenmenger’s syndrome and PPH; however, it was relevantly higher in SVPH. Maternal prognosis depends on the early diagnosis of PVD, early hospital admission, individually tailored treatment during pregnancy and medical therapy and care focused on the postpartal period.
Large quantities of coal are transported through tropical regions; however, little is known about the sub-lethal effects of coal contamination on tropical marine organisms, including fish. Here, we ...measured aerobic metabolism and gill morphology in a planktivorous coral reef damselfish, Acanthochromis polyacanthus to elucidate the sub-lethal effects of suspended coal particles over a range of coal concentrations and exposure durations. Differences in the standard oxygen consumption rates (MO2) between control fish and fish exposed to coal particles (38 and 73 mg L−1) were minimal and generally not dose dependent; however, the MO2 of fish exposed to 38 mg coal L−1 (21 days) and 73 mg coal L−1 (31 days) were both significantly higher than the MO2 of control fish. Chronic coal exposure (31 days) altered gill structure in the higher coal treatments (73 and 275 mg L−1), with fish exposed to 275 mg L−1 exhibiting significant reductions in gill mucous and thinning of lamellar and filament epithelium. These findings contribute to our limited understanding of the potential impacts of coal on tropical reef species; however, most of the observed effects occurred at high coal concentrations that are unlikely under most coal spill scenarios. Future studies should investigate other contamination scenarios such as the impacts of chronic exposures to lower concentrations of coal.
•Differences in standard oxygen consumption rates between control and coal exposed fish were generally not dose dependent•Chronic coal exposure (31 d) altered gill structure in the higher coal treatments•Coal concentrations considered most ecologically relevant did not elicit significant sub-lethal effects
MR tissue tagging allows the noninvasive assessment of the locally and temporally resolved motion pattern of the left ventricle. Alterations in cardiac torsion and diastolic relaxation of the left ...ventricle were studied in patients with aortic stenosis and were compared with those of healthy control subjects and championship rowers with physiological volume-overload hypertrophy.
Twelve aortic stenosis patients, 11 healthy control subjects with normal left ventricular function, and 11 world-championship rowers were investigated for systolic and diastolic heart wall motion on a basal and an apical level of the myocardium. Systolic torsion and untwisting during diastole were examined by use of a novel tagging technique (CSPAMM) that provides access to systolic and diastolic motion data. In the healthy heart, the left ventricle performs a systolic wringing motion, with a counterclockwise rotation at the apex and a clockwise rotation at the base. Apical untwisting precedes diastolic filling. In the athlete's heart, torsion and untwisting remain unchanged compared with those of the control subjects. In aortic stenosis patients, torsion is significantly increased and diastolic apical untwisting is prolonged compared with those of control subjects or athletes.
Torsional behavior as observed in pressure- and volume-overloaded hearts is consistent with current theoretical findings. A delayed diastolic untwisting in the pressure-overloaded hearts of the patients may contribute to a tendency toward diastolic dysfunction.
In this double-blind study, a combination of folate, vitamin B
12
, and pyridoxine was found to reduce the rate of restenosis in patients who had undergone coronary angioplasty. There was less ...benefit in patients who had received stents than in those who had not. Vitamin therapy also resulted in lower plasma homocysteine levels, a potential mechanism of the clinical effect.
A relatively simple and inexpensive intervention reduced the risk of restenosis after coronary angioplasty.
The occurrence of restenosis after percutaneous coronary angioplasty remains an important limitation of the procedure,
1
and effective pharmacotherapy has been elusive.
2
–
5
Thus, the observation that the total plasma homocysteine level is an important predictor of cardiovascular risk
6
,
7
and correlates with the severity of coronary artery disease
8
,
9
has led to interest in its potential role in restenosis. Although the mechanism of homocysteine-induced vascular damage is not known, a number of potential links have been suggested.
10
–
14
We have previously shown that patients with plasma homocysteine levels below 9 μmol per liter have a 49 percent lower rate of . . .
The EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM) is a cryogenic balloon-borne instrument that will survey galaxy and star formation history over cosmological timescales. Rather ...than identifying individual objects, EXCLAIM will be a pathfinder to demonstrate an intensity mapping approach, which measures the cumulative redshifted line emission. EXCLAIM will operate at 420–540 GHz with a spectral resolution
R
=
512
to measure the integrated CO and CII in redshift windows spanning
0
<
z
<
3.5
. CO and CII line emissions are key tracers of the gas phases in the interstellar medium involved in star formation processes. EXCLAIM will shed light on questions such as why the star formation rate declines at
z
<
2
, despite continued clustering of the dark matter. The instrument will employ an array of six superconducting integrated grating-analog spectrometers (
μ
-Spec) coupled to microwave kinetic inductance detectors. Here we present an overview of the EXCLAIM instrument design and status.
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