| 1. |
- Tarrío, Diego, et al.
(författare)
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Neutron-induced fission cross sections of Th-232 and U-233 up to 1 GeV using parallel plate avalanche counters at the CERN n_TOF facility
- 2023
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 107:4
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Tidskriftsartikel (refereegranskat)abstract
- The neutron-induced fission cross sections of Th-232 and U-233 were measured relative to U-235 in a wide neutron energy range up to 1 GeV (and from fission threshold in the case of Th-232, and from 0.7 eV in case of U-233), using the white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. Parallel plate avalanche counters (PPACs) were used, installed at the Experimental Area 1 (EAR1), which is located at 185 m from the neutron spallation target. The anisotropic emission of fission fragments were taken into account in the detection efficiency by using, in the case of U-233, previous results available in EXFOR, whereas in the case of Th-232 these data were obtained from our measurement, using PPACs and targets tilted 45 degrees with respect to the neutron beam direction. Finally, the obtained results are compared with past measurements and major evaluated nuclear data libraries. Calculations using the high-energy reaction models INCL++ and ABLA07 were performed and some of their parameters were modified to reproduce the experimental results. At high energies, where no other neutron data exist, our results are compared with experimental data on proton-induced fission. Moreover, the dependence of the fission cross section at 1 GeV with the fissility parameter of the target nucleus is studied by combining those ( p, f) data with our (n, f) data on Th-232 and U-233 and on other isotopes studied earlier at n_TOF using the same experimental setup.
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| 2. |
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| 3. |
- Zitouni, J., et al.
(författare)
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Children with psoriasis and COVID-19 : factors associated with an unfavourable COVID-19 course, and the impact of infection on disease progression (Chi-PsoCov registry)
- 2022
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Ingår i: Journal of the European Academy of Dermatology and Venereology. - : John Wiley & Sons. - 0926-9959 .- 1468-3083. ; 36:11, s. 2076-2086
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Tidskriftsartikel (refereegranskat)abstract
- Background The COVID-19 pandemic has raised questions regarding the management of chronic skin diseases, especially in patients on systemic treatments. Data concerning the use of biologics in adults with psoriasis are reassuring, but data specific to children are missing. Moreover, COVID-19 could impact the course of psoriasis in children. Objectives The aim of this study was therefore to assess the impact of COVID-19 on the psoriasis of children, and the severity of the infection in relation to systemic treatments. Methods We set up an international registry of paediatric psoriasis patients. Children were included if they were under 18 years of age, had a history of psoriasis, or developed it within 1 month of COVID-19 and had COVID-19 with or without symptoms. Results One hundred and twenty episodes of COVID-19 in 117 children (mean age: 12.4 years) were reported. The main clinical form of psoriasis was plaque type (69.4%). Most children were without systemic treatment (54.2%); 33 (28.3%) were on biologic therapies, and 24 (20%) on non-biologic systemic drugs. COVID-19 was confirmed in 106 children (88.3%) and 3 children had two COVID-19 infections each. COVID-19 was symptomatic for 75 children (62.5%) with a mean duration of 6.5 days, significantly longer for children on non-biologic systemic treatments (P = 0.02) and without systemic treatment (P = 0.006) when compared with children on biologics. The six children who required hospitalization were more frequently under non-biologic systemic treatment when compared with the other children (P = 0.01), and particularly under methotrexate (P = 0.03). After COVID-19, the psoriasis worsened in 17 cases (15.2%). Nine children (8%) developed a psoriasis in the month following COVID-19, mainly a guttate form (P = 0.01). Discussion Biologics appear to be safe with no increased risk of severe form of COVID-19 in children with psoriasis. COVID-19 was responsible for the development of psoriasis or the worsening of a known psoriasis for some children.
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| 4. |
- Wood, C. M., et al.
(författare)
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Time-dependent visibility modelling of a relativistic jet in the X-ray binary MAXI J1803-298
- 2023
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 522:1, s. 70-89
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Tidskriftsartikel (refereegranskat)abstract
- Tracking the motions of transient jets launched by low-mass X-ray binaries (LMXBs) is critical for determining the moment of jet ejection, and identifying any corresponding signatures in the accretion flow. However, these jets are often highly variable and can travel across the resolution element of an image within a single observation, violating a fundamental assumption of aperture synthesis. We present a novel approach in which we directly fit a single time-dependent model to the full set of interferometer visibilities, where we explicitly parametrize the motion and flux density variability of the emission components, to minimize the number of free parameters in the fit, while leveraging information from the full observation. This technique allows us to detect and characterize faint, fast-moving sources, for which the standard time binning technique is inadequate. We validate our technique with synthetic observations, before applying it to three Very Long Baseline Array (VLBA) observations of the black hole candidate LMXB MAXI J1803-298 during its 2021 outburst. We measured the proper motion of a discrete jet component to be 1.37 ± 0.14 mas h-1, and thus we infer an ejection date of MJD 59348.08+0.05-0.06, which occurs just after the peak of a radio flare observed by the Australia Telescope Compact Array (ATCA) and the Atacama Large Millimeter/Sub-Millimeter Array (ALMA), while MAXI J1803-298 was in the intermediate state. Further development of these new VLBI analysis techniques will lead to more precise measurements of jet ejection dates, which, combined with dense, simultaneous multiwavelength monitoring, will allow for clearer identification of jet ejection signatures in the accretion flow.
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| 5. |
- Saikia, Payaswini, et al.
(författare)
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A Multiwavelength Study of GRS 1716-249 in Outburst: Constraints on Its System Parameters
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 932:1
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed study of the evolution of the Galactic black hole transient GRS 1716-249 during its 2016-2017 outburst at optical (Las Cumbres Observatory), mid-infrared (Very Large Telescope), near-infrared (Rapid Eye Mount telescope), and ultraviolet (the Neil Gehrels Swift Observatory Ultraviolet/Optical Telescope) wavelengths, along with archival radio and X-ray data. We show that the optical/near-infrared and UV emission of the source mainly originates from a multi-temperature accretion disk, while the mid-infrared and radio emission are dominated by synchrotron emission from a compact jet. The optical/UV flux density is correlated with the X-ray emission when the source is in the hard state, consistent with an X-ray irradiated accretion disk with an additional contribution from the viscous disk during the outburst fade. We find evidence for a weak, but highly variable jet component at mid-infrared wavelengths. We also report the long-term optical light curve of the source and find that the quiescent i'-band magnitude is 21.39 +/- 0.15 mag. Furthermore, we discuss how previous estimates of the system parameters of the source are based on various incorrect assumptions, and so are likely to be inaccurate. By comparing our GRS 1716-249 data set to those of other outbursting black hole X-ray binaries, we find that while GRS 1716-249 shows similar X-ray behavior, it is noticeably optically fainter, if the literature distance of 2.4 kpc is adopted. Using several lines of reasoning, we argue that the source distance is further than previously assumed in the literature, likely within 4-17 kpc, with a most likely range of similar to 4-8 kpc.
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| 6. |
- Vincentelli, Federico M., et al.
(författare)
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A shared accretion instability for black holes and neutron stars
- 2023
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 615:7950, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- Accretion disks around compact objects are expected to enter an unstable phase at high luminosity1. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion and refilling of the inner disk on short timescales2. Such a scenario, however, has only been quantitatively verified for a single stellar-mass black hole3-5. Although there are hints of these cycles in a few isolated cases6-10, their apparent absence in the variable emission of most bright accreting neutron stars and black holes has been a continuing puzzle11. Here we report the presence of the same multiwavelength instability around an accreting neutron star. Moreover, we show that the variability across the electromagnetic spectrum-from radio to X-ray-of both black holes and neutron stars at high accretion rates can be explained consistently if the accretion disks are unstable, producing relativistic ejections during transitions that deplete or refill the inner disk. Such a new association allows us to identify the main physical components responsible for the fast multiwavelength variability of highly accreting compact objects.
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| 7. |
- Zanotti, Roberta, et al.
(författare)
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Refined diagnostic criteria for bone marrow mastocytosis : a proposal of the European competence network on mastocytosis
- 2022
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Ingår i: Leukemia. - : Springer Nature. - 0887-6924 .- 1476-5551. ; 36:2, s. 516-524
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Tidskriftsartikel (refereegranskat)abstract
- In the current classification of the World Health Organization (WHO), bone marrow mastocytosis (BMM) is a provisional variant of indolent systemic mastocytosis (ISM) defined by bone marrow involvement and absence of skin lesions. However, no additional diagnostic criteria for BMM have been proposed. Within the registry dataset of the European Competence Network on Mastocytosis, we compared characteristics and outcomes of 390 patients with BMM and 1175 patients with typical ISM. BMM patients were significantly older, predominantly male, had lower tryptase and lower burden of neoplastic mast cells, and displayed a higher frequency of allergic reactions, mainly triggered by Hymenoptera, than patients with typical ISM. The estimated 10-year progression-free survival of BMM and typical ISM was 95.9% and 92.6%, respectively. In BMM patients defined by WHO-based criteria, the presence of one B-Finding and tryptase level >= 125 ng/mL were identified as risk factors for progression in multivariate analyses. BMM patients without any of these risk factors were found to have better progression-free survival (p < 0.05) and better overall survival (p < 0.05) than other ISM patients. These data support the proposal to define BMM as a separate SM variant characterized by SM criteria, absence of skin lesions, absence of B-Findings, and tryptase levels <125 ng/mL.
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| 8. |
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| 9. |
- Echiburu-Trujillo, Constanza, et al.
(författare)
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Chasing the Break: Tracing the Full Evolution of a Black Hole X-Ray Binary Jet with Multiwavelength Spectral Modeling
- 2024
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 962:2
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Tidskriftsartikel (refereegranskat)abstract
- Black hole (BH) X-ray binaries (XRBs) are ideal targets to study the connection between accretion inflow and jet outflow. Here we present quasi-simultaneous, multiwavelength observations of the Galactic BH system MAXI J1820+070, throughout its 2018-2019 outburst. Our data set includes coverage from the radio through X-ray bands from 17 different instruments/telescopes, and encompasses 19 epochs over a 7 month period, resulting in one of the most well-sampled multiwavelength data sets of a BH XRB outburst to date. With our data, we compile and model the broadband spectra of this source using a phenomenological model that includes emission from the jet, a companion star, and an accretion flow. This modeling allows us to track the evolution of the spectral break in the jet spectrum, a key observable that samples the jet launching region. We find that the spectral break location changes over at least approximate to 3 orders of magnitude in electromagnetic frequency over this period. Using these spectral break measurements, we link the full cycle of jet behavior, including the rising, quenching, and reignition, to the changing accretion flow properties as the source evolves through its different accretion states. Our analysis shows consistent jet behavior with other sources in similar phases of their outbursts, reinforcing the idea that jet quenching and recovery may be a global feature of BH XRB systems in outburst. Our results also provide valuable evidence supporting a close connection between the geometry of the inner accretion flow and the base of the jet.
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| 10. |
- Fuchs, David, et al.
(författare)
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Scoring the Risk of Having Systemic Mastocytosis in Adult Patients with Mastocytosis in the Skin
- 2021
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 2213-2198 .- 2213-2201. ; 9:4, s. 1705-1712.e4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Mastocytosis in adults often presents with skin lesions. A bone marrow biopsy is necessary to confirm or exclude the presence of systemic mastocytosis (SM) in these cases. When a bone marrow biopsy is not performed, the provisional diagnosis is mastocytosis in the skin (MIS). No generally accepted scoring system has been established to estimate the risk of SM in these patients. OBJECTIVE: To develop a risk score to predict SM in adults with MIS. METHODS: We examined 1145 patients with MIS from the European Competence Network on Mastocytosis Registry who underwent a bone marrow biopsy. A total of 944 patients had SM and 201 patients had cutaneous mastocytosis; 63.7% were female, and 36.3% were male. Median age was 44 +/- 13.3 years. The median serum tryptase level amounted to 29.3 +/- 81.9 ng/mL. We established a multivariate regression model using the whole population of patients as a training and validation set (bootstrapping). A risk score was developed and validated with receiver-operating curves. RESULTS: In the multivariate model, the tryptase level (P < .001), constitutional/cardiovascular symptoms (P = .014), and bone symptoms/osteoporosis (P < .001) were independent predictors of SM (P < .001; sensitivity, 90.7%; specificity, 69.1%). A 6-point risk score was established (risk, 10.7%-98.0%) and validated. CONCLUSIONS: Using a large data set of the European Competence Network on Mastocytosis Registry, we created a risk score to predict the presence of SM in patients with MIS. Although the score will need further validation in independent cohorts, our score seems to discriminate safely between patients with SM and with pure cutaneous mastocytosis. (C) 2020 American Academy of Allergy, Asthma & Immunology
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