80 research outputs found
On the nature of the hard X-ray sources SWIFTJ1907.3-2050, IGRJ12123-5802 and IGRJ19552+0044
The INTEGRAL and Swift hard X-ray surveys have identified a large number of
new sources, among which many are proposed as Cataclysmic Variables (CVs). Here
we present the first detailed study of three X-ray selected CVs, Swift
J1907.3-2050, IGRJ12123-5802, and IGRJ19552+0044 based on XMM-Newton, Suzaku,
Swift observations and ground based optical and archival nIR/IR data. Swift
J1907.3-2050 is highly variable from hours to months-years at all wavelengths.
No coherent X-ray pulses are detected but rather transient features. The X-ray
spectrum reveals a multi-temperature optically thin plasma absorbed by complex
neutral material and a soft black body component arising from a small area.
These characteristics are remarkably similar to those observed in magnetic CVs.
A supra-solar abundance of nitrogen could arise from nuclear processed material
from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with
the second longest (20.82 h) binary period. IGRJ12123-5802 is variable in the
X-rays on a timescale of ~7.6 h. No coherent pulsations are detected, but its
spectral characteristics suggest that it could be a magnetic CV of the
Intermediate Polar (IP) type. IGRJ19552+0044 shows two X-ray periods, 1.38 h
and 1.69 h and a X-ray spectrum characterized by a multi-temperature plasma
with little absorption.We derive a low accretion rate, consistent with a CV
below the orbital period gap. Its peculiar nIR/IR spectrum suggests a
contribution from cyclotron emission. It could either be a pre-polar or an IP
with the lowest degree of asynchronism.Comment: Accepted for publication in MNRAS. 14 pages, 11 figures, 5 table
On the nature of the hard X-ray sources SWIFT J1907.3-2050, IGR J12123-5802 and IGR J19552+0044
The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here, we present the first detailed study of three X-ray-selected CVs, Swift J1907.3-2050, IGR J12123-5802 and IGR J19552+0044 based on XMM-Newton, Suzaku, Swift observations and groundbased optical and archival (near-IR) nIR/IR data. Swift J1907.3-2050 is highly variable from hours to months-years at all wavelengths. No coherent X-ray pulses are detected but rather transient features. The X-ray spectrum reveals a multitemperature optically thin plasma absorbed by complex neutral material and a soft blackbody component arising from a small area. These characteristics are remarkably similar to those observed inmagnetic CVs. A suprasolar abundance of nitrogen could arise from nuclear processed material from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with the second longest (20.82 h) binary period. IGR J12123-5802 is variable in the X-rays on a time-scale of ≳ 7.6 h. No coherent pulsations are detected, but its spectral characteristics suggest that it could be a magnetic CV of the Intermediate Polar (IP) type. IGR J19552+0044 shows two X-ray periods, ~1.38 h and ~1.69 h and an X-ray spectrum characterized by a multitemperature plasma with little absorption. We derive a low accretion rate, consistent with a CV below the orbital period gap. Its peculiar nIR/IR spectrum suggests a contribution from cyclotron emission. It could either be a pre-polar or an IP with the lowest degree of asynchronism.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
IGR J19552+0044: A new asynchronous short period polar: "Filling the gap between intermediate and ordinary polars"
Based on XMM--Newton X-ray observations IGR J19552+0044 appears to be either
a pre-polar or an asynchronous polar. We conducted follow-up optical
observations to identify the sources and periods of variability precisely and
to classify this X-ray source correctly. Extensive multicolor photometric and
medium- to high-resolution spectroscopy observations were performed and period
search codes were applied to sort out the complex variability of the object. We
found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric
(83.599+/-0.002m) periods that we ascribe to the white dwarf (WD)\ spin period
and binary orbital period, respectively. This confirms that IGR J19552+0044 is
an asynchronous polar. Wavelength-dependent variability and its continuously
changing shape point at a cyclotron emission from a magnetic WD with a
relatively low magnetic field below 20 MG.
The difference between the WD spin period and the binary orbital period
proves that IGR J19552+0044 is a polar with the largest known degree of
asynchronism (0.97 or 3%).Comment: 9 pages, 10 figures, A&A accepte
On the nature of the hard X-ray sources SWIFT J1907.3-2050, IGR J12123-5802 and IGR J19552+0044
The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here, we present the first detailed study of three X-ray-selected CVs, Swift J1907.3-2050, IGR J12123-5802 and IGR J19552+0044 based on XMM-Newton, Suzaku, Swift observations and groundbased optical and archival (near-IR) nIR/IR data. Swift J1907.3-2050 is highly variable from hours to months-years at all wavelengths. No coherent X-ray pulses are detected but rather transient features. The X-ray spectrum reveals a multitemperature optically thin plasma absorbed by complex neutral material and a soft blackbody component arising from a small area. These characteristics are remarkably similar to those observed inmagnetic CVs. A suprasolar abundance of nitrogen could arise from nuclear processed material from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with the second longest (20.82 h) binary period. IGR J12123-5802 is variable in the X-rays on a time-scale of ≳ 7.6 h. No coherent pulsations are detected, but its spectral characteristics suggest that it could be a magnetic CV of the Intermediate Polar (IP) type. IGR J19552+0044 shows two X-ray periods, ~1.38 h and ~1.69 h and an X-ray spectrum characterized by a multitemperature plasma with little absorption. We derive a low accretion rate, consistent with a CV below the orbital period gap. Its peculiar nIR/IR spectrum suggests a contribution from cyclotron emission. It could either be a pre-polar or an IP with the lowest degree of asynchronism.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
Mental health of migrants with pre-migration exposure to armed conflict: a systematic review and meta-analysis.
BACKGROUND
Exposure to armed conflict has been associated with negative mental health consequences. We aimed to estimate the prevalence of generalised anxiety disorder, major depressive disorder, and post-traumatic stress disorder among migrants exposed to armed conflict.
METHODS
In this systematic review and meta-analysis, we searched online databases (Cochrane Library, Embase, LILACS, PsycInfo [via Ovid], PubMed, and Web of Science Core Collection) for relevant observational studies published between Jan 1, 1994, and June 28, 2021. We included studies that used standardised psychiatric interviews to assess generalised anxiety disorder, major depressive disorder, or post-traumatic stress disorder among migrants (refugees or internally displaced persons; aged ≥18 years) with pre-migration exposure to armed conflict. We excluded studies in which exposure to armed conflict could not be ascertained, studies that included a clinical population or people with chronic diseases that can trigger the onset of mental disease, and studies published before 1994. We used a random effects model to estimate each mental health disorder's pooled prevalence and random effects meta-regression to assess sources of heterogeneity. Two independent reviewers assessed the risk of bias for each study using the Joanna Briggs Institute Checklist for Prevalence Studies. The protocol was registered with PROSPERO, CRD42020209251.
FINDINGS
Of the 13 935 studies identified, 34 met our inclusion criteria; these studies accounted for 15 549 migrants. We estimated a prevalence of current post-traumatic stress disorder of 31% (95% CI 23-40); prevalence of current major depressive disorder of 25% (17-34); and prevalence of generalised anxiety disorder of 14% (5-35). Younger age was associated with a higher prevalence of current post-traumatic stress disorder (odds ratio 0·95 [95% CI 0·90-0·99]), lifetime post-traumatic stress disorder (0·88 [0·83-0·92]), and current generalised anxiety disorder (0·87 [0·78-0·97]). A longer time since displacement was associated with a lower lifetime prevalence of post-traumatic stress disorder (0·88 [0·81-0·95]) and major depressive disorder (0·81 [0·77-0·86]). Migrating to a middle-income (8·09 [3·06-21·40]) or low-income (39·29 [11·96-129·70]) country was associated with increased prevalence of generalised anxiety disorder.
INTERPRETATION
Migrants who are exposed to armed conflict are at high risk of mental health disorders. The mental health-care needs of migrants should be assessed soon after resettlement, and adequate care should be provided, with particular attention paid to young adults.
FUNDING
Marie Skłodowska-Curie Actions (Horizon 2020-COFUND), MinCiencias (Colombia), and Swiss National Science Foundation
Intensive disc-reverberation mapping of Fairall 9 : 1st year of Swift & LCO monitoring
Funding: UK STFC grant ST/R000824/1 (KH).We present results of time-series analysis of the first year of the Fairall 9 intensive disc-reverberation campaign. We used Swift and the Las Cumbres Observatory global telescope network to continuously monitor Fairall 9 from X-rays to near-infrared at a daily to sub-daily cadence. The cross-correlation function between bands provides evidence for a lag spectrum consistent with the τ ∝ λ4/3 scaling expected for an optically thick, geometrically thin blackbody accretion disc. Decomposing the flux into constant and variable components, the variable component's spectral energy distribution is slightly steeper than the standard accretion disc prediction. We find evidence at the Balmer edge in both the lag and flux spectra for an additional bound-free continuum contribution that may arise from reprocessing in the broad-line region. The inferred driving light curve suggests two distinct components, a rapidly variable ( 100 days) component with an opposite lag to the reverberation signal.PostprintPeer reviewe
Intensive disc-reverberation mapping of Fairall 9: 1st year of Swift & LCO monitoring
We present results of time-series analysis of the first year of the Fairall 9 intensive disc-reverberation campaign. We used Swift and the Las Cumbres Observatory global telescope network to continuously monitor Fairall 9 from X-rays to near-infrared at a daily to sub-daily cadence. The cross-correlation function between bands provides evidence for a lag spectrum consistent with the scaling expected for an optically thick, geometrically thin blackbody accretion disc. Decomposing the flux into constant and variable components, the variable component's spectral energy distribution is slightly steeper than the standard accretion disc prediction. We find evidence at the Balmer edge in both the lag and flux spectra for an additional bound-free continuum contribution that may arise from reprocessing in the broad-line region. The inferred driving light curve suggests two distinct components, a rapidly variable ( days) component with an opposite lag to the reverberation signal
Novel prokaryotic expression of thioredoxin-fused insulinoma associated protein tyrosine phosphatase 2 (IA-2), its characterization and immunodiagnostic application
Background
The insulinoma associated protein tyrosine phosphatase 2 (IA-2) is one of the immunodominant autoantigens involved in the autoimmune attack to the beta-cell in Type 1 Diabetes Mellitus. In this work we have developed a complete and original process for the production and recovery of the properly folded intracellular domain of IA-2 fused to thioredoxin (TrxIA-2ic) in Escherichia coli GI698 and GI724 strains. We have also carried out the biochemical and immunochemical characterization of TrxIA-2icand design variants of non-radiometric immunoassays for the efficient detection of IA-2 autoantibodies (IA-2A).
Results
The main findings can be summarized in the following statements: i) TrxIA-2ic expression after 3 h of induction on GI724 strain yielded ≈ 10 mg of highly pure TrxIA-2ic/L of culture medium by a single step purification by affinity chromatography, ii) the molecular weight of TrxIA-2ic (55,358 Da) could be estimated by SDS-PAGE, size exclusion chromatography and mass spectrometry, iii) TrxIA-2ic was properly identified by western blot and mass spectrometric analysis of proteolytic digestions (63.25 % total coverage), iv) excellent immunochemical behavior of properly folded full TrxIA-2ic was legitimized by inhibition or displacement of [35S]IA-2 binding from IA-2A present in Argentinian Type 1 Diabetic patients, v) great stability over time was found under proper storage conditions and vi) low cost and environmentally harmless ELISA methods for IA-2A assessment were developed, with colorimetric or chemiluminescent detection.
Conclusions
E. coli GI724 strain emerged as a handy source of recombinant IA-2ic, achieving high levels of expression as a thioredoxin fusion protein, adequately validated and applicable to the development of innovative and cost-effective immunoassays for IA-2A detection in most laboratories.Fil: Guerra, Luciano Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Faccinetti, Natalia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Trabucchi, Aldana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Rovitto, Bruno David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Sabljic, Adriana Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Poskus, Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Iacono, Ruben Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Valdez, Silvina Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; Argentin
AGN STORM 2. IV. Swift X-ray and ultraviolet/optical monitoring of Mrk 817
The AGN STORM 2 campaign is a large, multiwavelength reverberation mapping
project designed to trace out the structure of Mrk 817 from the inner accretion
disk to the broad emission line region and out to the dusty torus. As part of
this campaign, Swift performed daily monitoring of Mrk 817 for approximately 15
months, obtaining observations in X-rays and six UV/optical filters. The X-ray
monitoring shows that Mrk 817 was in a significantly fainter state than in
previous observations, with only a brief flare where it reached prior flux
levels. The X-ray spectrum is heavily obscured. The UV/optical light curves
show significant variability throughout the campaign and are well correlated
with one another, but uncorrelated with the X-rays. Combining the Swift
UV/optical light curves with Hubble UV continuum light curves, we measure
interband continuum lags, , that increase with increasing
wavelength roughly following , the
dependence expected for a geometrically thin, optically thick, centrally
illuminated disk. Modeling of the light curves reveals a period at the
beginning of the campaign where the response of the continuum is suppressed
compared to later in the light curve - the light curves are not simple shifted
and scaled versions of each other. The interval of suppressed response
corresponds to a period of high UV line and X-ray absorption, and reduced
emission line variability amplitudes. We suggest that this indicates a
significant contribution to the continuum from the broad line region gas that
sees an absorbed ionizing continuum.Comment: 20 pages, 13 figures, 3 tables, accepted for publication in Ap
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