Introduction:
Ultraluminous X-ray sources (ULXs) represent an extreme class of accreting compact objects: from the identification of some of the accretors as neutron stars to the detection of ...powerful winds travelling at 0.1–0.2 c, the increasing evidence points towards ULXs harbouring stellar-mass compact objects undergoing highly super-Eddington accretion. Measuring their intrinsic properties, such as the accretion rate onto the compact object, the outflow rate, the masses of accretor/companion-hence their progenitors, lifetimes, and future evolution-is challenging due to ULXs being mostly extragalactic and in crowded fields. Yet ULXs represent our best opportunity to understand super-Eddington accretion physics and the paths through binary evolution to eventual double compact object binaries and gravitational-wave sources.
Methods:
Through a combination of end-to-end and single-source simulations, we investigate the ability of HEX-P to study ULXs in the context of their host galaxies and compare it to XMM-Newton and NuSTAR, the current instruments with the most similar capabilities.
Results:
HEX-P’s higher sensitivity, which is driven by its narrow point-spread function and low background, allows it to detect pulsations and broad spectral features from ULXs better than XMM-Newton and NuSTAR.
Discussion:
We describe the value of HEX-P in understanding ULXs and their associated key physics, through a combination of broadband sensitivity, timing resolution, and angular resolution, which make the mission ideal for pulsation detection and low-background, broadband spectral studies.
Aims.
We introduce a method for extracting spectral information from energy-resolved light curves folded at the neutron star spin period (known as pulse profiles) in accreting X-ray binaries. Spectra ...of these sources are sometimes characterized by features superimposed on a smooth continuum, such as iron emission lines and cyclotron resonant scattering features. We address here the question on how to derive quantitative constraints on such features from energy-dependent changes in the pulse profiles.
Methods.
We developed a robust method for determining in each energy-selected bin the value of the pulsed fraction using the fast Fourier transform opportunely truncated at the number of harmonics needed to satisfactorily describe the actual profile. We determined the uncertainty on this value by sampling through Monte Carlo simulations a total of 1000 faked profiles. We rebinned the energy-resolved pulse profiles to have a constant minimum signal-to-noise ratio throughout the whole energy band. Finally we characterize the dependence of the energy-resolved pulsed fraction using a phenomenological polynomial model and search for features corresponding to spectral signatures of iron emission or cyclotron lines using Gaussian line profiles.
Results.
We apply our method to a representative sample of
NuSTAR
observations of well-known accreting X-ray pulsars. We show that, with this method, it is possible to characterize the pulsed fraction spectra, and to constrain the position and widths of such features with a precision comparable with the spectral results. We also explore how harmonic decomposition, correlation, and lag spectra might be used as additional probes for detection and characterization of such features.
ABSTRACT
We studied the spectral changes of the high-mass X-ray binary system LMC X-4 to understand the origin and mechanisms beyond its superorbital modulation (30.4 d). To this aim, we obtained a ...monitoring campaign with Swift/XRT (0.3–10 keV) and complemented these data with the years-long Swift/BAT survey data (15–60 keV). We found a self-consistent, physically motivated, description of the broad-band X-ray spectrum using a Swift/XRT and a NuSTAR observation at the epoch of maximum flux. We decomposed the spectrum into the sum of a bulk + thermal Comptonization, a disc reflection component, and a soft contribution from a standard Shakura–Sunyaev accretion disc. We applied this model to 20 phase-selected Swift spectra along the superorbital period. We found a phase-dependent flux ratio of the different components, whereas the absorption column does not vary significantly. The disc emission is decoupled with respect to the hard flux. We interpret this as a geometrical effect in which the inner parts of the disc are tilted with respect to the obscuring outer regions.
Abstract
We report the discovery of the unusually bright long-duration gamma-ray burst (GRB), GRB 221009A, as observed by the Neil Gehrels Swift Observatory (Swift), Monitor of All-sky X-ray Image, ...and Neutron Star Interior Composition Explorer Mission. This energetic GRB was located relatively nearby (
z
= 0.151), allowing for sustained observations of the afterglow. The large X-ray luminosity and low Galactic latitude (
b
= 4.°3) make GRB 221009A a powerful probe of dust in the Milky Way. Using echo tomography, we map the line-of-sight dust distribution and find evidence for significant column densities at large distances (≳10 kpc). We present analysis of the light curves and spectra at X-ray and UV–optical wavelengths, and find that the X-ray afterglow of GRB 221009A is more than an order of magnitude brighter at
T
0
+ 4.5 ks than that from any previous GRB observed by Swift. In its rest frame, GRB 221009A is at the high end of the afterglow luminosity distribution, but not uniquely so. In a simulation of randomly generated bursts, only 1 in 10
4
long GRBs were as energetic as GRB 221009A; such a large
E
γ
,iso
implies a narrow jet structure, but the afterglow light curve is inconsistent with simple top-hat jet models. Using the sample of Swift GRBs with redshifts, we estimate that GRBs as energetic and nearby as GRB 221009A occur at a rate of ≲1 per 1000 yr—making this a truly remarkable opportunity unlikely to be repeated in our lifetime.
Objective
The primary aim of this article was to describe SARS‐CoV‐2 infection among pregnant women during the wild‐type and Alpha‐variant periods in Italy. The secondary aim was to compare the ...impact of the virus variants on the severity of maternal and perinatal outcomes.
Design
National population‐based prospective cohort study.
Setting
A total of 315 Italian maternity hospitals.
Sample
A cohort of 3306 women with SARS‐CoV‐2 infection confirmed within 7 days of hospital admission.
Methods
Cases were prospectively reported by trained clinicians for each participating maternity unit. Data were described by univariate and multivariate analyses.
Main outcome measures
COVID‐19 pneumonia, ventilatory support, intensive care unit (ICU) admission, mode of delivery, preterm birth, stillbirth, and maternal and neonatal mortality.
Results
We found that 64.3% of the cohort was asymptomatic, 12.8% developed COVID‐19 pneumonia and 3.3% required ventilatory support and/or ICU admission. Maternal age of 30–34 years (OR 1.43, 95% CI 1.09–1.87) and ≥35 years (OR 1.62, 95% CI 1.23–2.13), citizenship of countries with high migration pressure (OR 1.75, 95% CI 1.36–2.25), previous comorbidities (OR 1.49, 95% CI 1.13–1.98) and obesity (OR 1.72, 95% CI 1.29–2.27) were all associated with a higher occurrence of pneumonia. The preterm birth rate was 11.1%. In comparison with the pre‐pandemic period, stillbirths and maternal and neonatal deaths remained stable. The need for ventilatory support and/or ICU admission among women with pneumonia increased during the Alpha‐variant period compared with the wild‐type period (OR 3.24, 95% CI 1.99–5.28).
Conclusions
Our results are consistent with a low risk of severe COVID‐19 disease among pregnant women and with rare adverse perinatal outcomes. During the Alpha‐variant period there was a significant increase of severe COVID‐19 illness. Further research is needed to describe the impact of different SARS‐CoV‐2 viral strains on maternal and perinatal outcomes.
Tweetable
The rate of severe COVID‐19 disease increased during the Alpha‐variant period compared with the wild‐type period.
Linked article This article is commented on by J G Thornton, p. 232 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471-0528.16981.
Background
ypN0 following induction treatment for advanced esophageal cancer improves survival. Importance of how ypN0 is achieved is unknown. This study evaluates survival in “natural” N0 (cN0/ypN0) ...and “downstaged” N0 (cN+/ypN0) patients.
Methods
Among patients treated with induction treatment and surgery, 83 CT scans were retrieved in digital format and re-evaluated by a radiologist, blinded to pathological nodal status: 28 natural N0, 37 downstaged N0, and 18 ypN+. Impact of N0 classification on survival and associations with survival were identified.
Results
Survival varied with ypN: 3-year survival was 84 % for natural N0 patients, 59 % for downstaged N0, and 20 % for ypN+ (
p
< .001). Compared with natural N0 patients, risk of cancer mortality was 3.8 for downstaged N0 and 7.6 for ypN+ (
p
= .01). Survival was also stratified by ypT: compared with ypT0 natural N0, who had the best survival, intermediate survival was seen in ypT+ natural N0 hazard ratio (HR), 1.3 and ypT0 downstaged N0 (HR, 1.8), and poor survival in ypT+ downstaged N0 (HR, 9.5) and ypN+ (HR, 12.0) (
p
= .026).
Conclusions
Natural N0 and downstaged N0 patients are different clinical entities: downstaging cN+ with induction treatment producing downstaged N0 improves survival only if there is concomitant primary cancer downstaging to ypT0. Intermediate survival is seen in downstaged N0 patients with complete tumor response. Natural N0 patients experience intermediate survival with incomplete response (ypT+). Complete response in natural N0 patients produces the best survival. Means of obtaining ypN0 status matters and requires a complete response for downstaged N0 patients to benefit from induction treatment.
Childbirth Care among SARS-CoV-2 Positive Women in Italy Donati, Serena; Corsi, Edoardo; Salvatore, Michele Antonio ...
International journal of environmental research and public health,
04/2021, Letnik:
18, Številka:
8
Journal Article
Recenzirano
Odprti dostop
The new coronavirus emergency spread to Italy when little was known about the infection's impact on mothers and newborns. This study aims to describe the extent to which clinical practice has ...protected childbirth physiology and preserved the mother-child bond during the first wave of the pandemic in Italy. A national population-based prospective cohort study was performed enrolling women with confirmed SARS-CoV-2 infection admitted for childbirth to any Italian hospital from 25 February to 31 July 2020. All cases were prospectively notified, and information on peripartum care (mother-newborn separation, skin-to-skin contact, breastfeeding, and rooming-in) and maternal and perinatal outcomes were collected in a structured form and entered in a web-based secure system. The paper describes a cohort of 525 SARS-CoV-2 positive women who gave birth. At hospital admission, 44.8% of the cohort was asymptomatic. At delivery, 51.9% of the mothers had a birth support person in the delivery room; the average caesarean section rate of 33.7% remained stable compared to the national figure. On average, 39.0% of mothers were separated from their newborns at birth, 26.6% practised skin-to-skin, 72.1% roomed in with their babies, and 79.6% of the infants received their mother's milk. The infants separated and not separated from their SARS-CoV-2 positive mothers both had good outcomes. At the beginning of the pandemic, childbirth raised awareness and concern due to limited available evidence and led to "better safe than sorry" care choices. An improvement of the peripartum care indicators was observed over time.
Implementation of high-quality national audits for perinatal mortality are needed to improve the registration of all perinatal deaths and the identification of the causes of death. This study aims to ...evaluate the implementation of a Regional Audit System for Stillbirth in Emilia-Romagna Region, Italy.
For each stillbirth (≥ 22 weeks of gestation, ≥ 500 g) occurred between January 1, 2014 to December 1, 2016 (n = 332), the same diagnostic workup was performed and a clinical record with data about mother and stillborn was completed. Every case was discussed in a multidisciplinary local audit to assess both the cause of death (ReCoDe classification) and the quality of care. Data were reviewed by the Regional Audit Group. Stillbirth rates, causes of death and the quality of care were established for each case.
Total stillbirth rate was 3.09 per 1000 births (332/107,528). Late stillbirth rate was 2.3 per 1000 (251/107,087). Sixteen stillbirths were not registered by the Regional Birth Register. The most prevalent cause of death was placental disorder (33.3%), followed by fetal (17.6%), cord (14.2%) and maternal disorders (7.6%). Unexplained cases were 14%. Compared to local audits, the regional group attributed different causes of death in 17% of cases. At multivariate analysis, infections were associated with early stillbirths (OR 3.38, CI95% 1.62-7.03) and intrapartum cases (OR 6.64, CI95% 2.61-17.02). Placental disorders were related to growth restriction (OR 1.89, CI95% 1.06-3.36) and were more frequent before term (OR 1.86, CI95% 1.11-3.15). Stillbirths judged possibly/probably preventable with a different management (10.9%) occurred more frequently in non-Italian women and were mainly related to maternal disorders (OR 6.64, CI95% 2.61-17.02).
Regional Audit System for Stillbirth improves the registration of stillbirth and allows to define the causes of death. Moreover, sub-optimal care was recognized, allowing to identify populations which could benefit from preventive measures.
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