Context. We seek clarification of the nature of X-ray sources detected in M 31. Here we focus on CXOM31 J004253.1+411422, the brightness of which suggests that it belongs to the class of ...ultraluminous X-ray sources. Aims. We determine the X-ray properties of sources detected in the XMM-Newton/Chandra monitoring program. We investigate spectral properties and search for periodic or quasi-periodic oscillations. Methods. A multicomponent model was applied to the spectra obtained from XMM-Newton data to evaluate the relative contributions from thermal and nonthermal emission. The time dependence of this ratio was evaluated over a period of forty days. We simultaneously fit data from XMM-Newton EPIC-pn, MOS1, and MOS2 detectors with (nonthermal) powerlaw and (thermal) multicolored blackbody. Results. The X-ray spectrum is best fit by the combination of a thermal component with kT ~ 1 keV and a powerlaw component with a photon index of approximately 2.6. From combined analysis of Chandra, Swift, and XMM-Newton data, the unabsorbed total luminosity of this source decreases from ~3.8 × 1039 erg s-1 in the first observation to ~0.5 × 1039 erg s-1 over a period of three months. The decay closely follows an exponential decline with a time constant of 32 days. The source spectrum evolves significantly, exhibiting a faster decline of the thermal component. We do not find evidence of any significant temporal features in the power density spectrum. The presence of a thermal component at kT ~ 1 keV in conjunction with a nonthermal high-energy tail, is also consistent with spectral properties of other ULXs in the “high state”. Conclusions. Our analysis indicates that the underlying source of this first ULX in M 31 is a black hole of mass, M ≥ 13M⊙, accreting near the Eddington limit, that underwent a transient outburst followed by an exponential decay reminiscent of transients associated with galactic X-ray novae.
Atopic dermatitis (AD) is increasingly common, with a point prevalence of more than 30% in some countries, and is characterized by visible skin lesions and intense itching.
The International Study of ...Life with Atopic Eczema (ISOLATE) is the first large-scale study to assess the effect of AD on the lives of patients and society, how patients and caregivers manage the condition, and how well patients and caregivers currently believe that AD is controlled.
Two thousand two patients (>13 years) and caregivers of children (2-13 years) with moderate-to-severe AD randomly selected from 8 countries underwent standardized telephone interviews using questions developed in collaboration with national eczema patient groups and physicians.
During each year, patients spend, on average, 1 of 3 days in flare. The majority of patients receive prescription topical corticosteroids to treat flares; however, 49% of respondents are concerned about using these agents. On average, patients and caregivers delay initiating treatment for 7 days after onset of a flare. Only 24% of patients and caregivers feel confident they can manage AD flares adequately. Seventy-five percent of caregivers and patients feel that being able to effectively control AD would be the single most important improvement to their or their child's quality of life. The avoidable secondary economic cost of AD is estimated at €2 billion per year across the European Union.
ISOLATE highlights the need to improve patients' control of AD to reduce the significant effect this condition has on the patient and society.
ISOLATE shows that patients with AD are untreated for half the time they are in flare, and thus there is an urgent need for physicians to ensure that the patients are educated and confident in using medication as prescribed to gain disease control.
V5116 Sgr (Nova Sgr 2005 No. 2), discovered on 2005 July 4, was observed with XMM-Newton in 2007 March, 20 months after the optical outburst. The X-ray spectrum shows that the nova had evolved to a ...pure supersoft X-ray source, with no significant emission at energies above 1 keV. The X-ray light curve shows abrupt decreases and increases of the flux by a factor similar to 8. It is consistent with a periodicity of 2.97 hr, the orbital period suggested by Dobrotka and coworkers, although the observation lasted just a little more than a whole period. We estimate the distance to V5116 Sgr to be 11 plus or minus 3 kpc. A simple blackbody model does not fit correctly the EPIC spectra, with X super(2) sub(v) > 4. In contrast, ONe-rich white dwarf atmosphere models provide a good fit, with N sub(H) = (1.3 plus or minus 0.1) x 10 super(21) cm super(-2), T = (0.1 plus or minus 0.1) x 10 super(5) K, and L = (3.9 plus or minus 0.8) x 10 super(37) (D/10kpc) super(2) ergs s super(-1) (during the high-flux periods). This is consistent with residual hydrogen burning in the white dwarf envelope. The white dwarf atmosphere temperature is the same both in the low- and the high-flux periods, ruling out an intrinsic variation of the X-ray source as the origin of the flux changes. We speculate that the X-ray light curve may result from a partial coverage by an asymmetric accretion disk in a high-inclination system.
We report on X-ray observations of Nova Sagittarii 1998 (V4633 Sgr) performed with XMM-Newton at three different epochs, 934, 1083, and 1265 days after discovery. The nova was detected with the EPIC ...cameras at all three epochs, with emission spanning the whole energy range from 0.2 to 10 keV. The X-ray spectra do not change significantly at the different epochs and are well fitted for the first and third observations with a multitemperature optically thin thermal plasma, while lower statistics in the second observations lead to a poorer fit. The thermal plasma emission is most probably originated in the shock heated ejecta, with chemical composition similar to that of a CO nova. However, we cannot completely rule out reestablished accretion as the origin of the emission. We also obtain upper limits for the temperature and luminosity of a potential white dwarf atmospheric component and conclude that hydrogen burning had already turned off by the time of our observations.
Context. Classical novae (CNe) have been found to represent the major class of supersoft X-ray sources (SSSs) in our neighbour galaxy M 31. Aims. We determine the properties and evolution of the two ...first SSSs ever discovered in the M 31 globular cluster (GC) system. Methods. We have used XMM-Newton, Chandra and Swift observations of the centre region of M 31 to discover both SSSs and to determine their X-ray light curves and spectra. We performed detailed analysis of XMM-Newton EPIC PN spectra of the source in Bol 111 (SS1) using blackbody and NLTE white dwarf (WD) atmosphere models. For the SSS in Bol 194 (SS2) we used optical monitoring data to search for an optical counterpart. Results. Both GC X-ray sources were classified as SSS. We identify SS1 with the CN M31N 2007-06b recently discovered in the M 31 GC Bol 111. For SS2 we did not find evidence for a recent nova outburst and can only provide useful constraints on the time of the outburst of a hypothetical nova. Conclusions. The only known CN in a M 31 GC can be identified with the first SSS found in a M 31 GC. We discuss the impact of our observations on the nova rate for the M 31 GC system.
Paediatric psoriasis - narrowband UVB treatment Zamberk, P; Velázquez, D; Campos, M ...
Journal of the European Academy of Dermatology and Venereology,
04/2010, Letnik:
24, Številka:
4
Journal Article
Recenzirano
Narrowband UV‐B is a safe and efficacious option for the treatment of adult psoriasis. However, the use of this therapy has been limited in children due to its long‐term carcinogenic potential. It ...has proven to be an adequate alternative in patients whose condition is refractory to topical treatment.
Aims To evaluate the efficacy and short‐term safety of narrowband UV‐B in the treatment of paediatric psoriasis, and to compare our results with those obtained in other studies on paediatric psoriasis.
Materials and methods Over a period of 2 years and 4 months, we administered narrowband UV‐B to 20 children diagnosed with psoriasis that was refractory to topical therapy. The therapeutic response was measured using the Psoriasis Area and Severity Index (PASI).
Results Between August 2005 and December 2007, 20 children received narrowband UV‐B. Their median age was 13 years (range, 5–17 years), and the median initial PASI score was 8.25 (2.7–22.2). A median of 28 (10–59) sessions was required to achieve clearance, reaching almost complete or total remission (median final PASI) in all but two patients. Six patients required a new therapeutic course because of relapse, and the mean duration of remission was 8 months (4–18). No patients experienced severe adverse events during therapy, and only one discontinued treatment, for unrelated reasons.
Discussion and conclusion Narrowband UV‐B for the treatment of paediatric psoriasis has received little attention in the literature. This treatment has been limited in children because of its potential long‐term carcinogenic effects, and most information has been extrapolated from adults. Nevertheless, narrowband UV‐B phototherapy is an effective and well‐tolerated therapeutic alternative in paediatric patients with severe psoriasis.
High-energy astrophysics polarimetry may significantly benefit from e-ASTROGAM and from AMEGO mission proposals, since to date limited polarimetric measurements were performed in this domain, ...exclusively under 1 MeV. The polarimetric potential of both missions was analyzed in the Compton regime by Monte Carlo mass model simulations with MEGAlib toolkit. The performance of e-ASTROGAM was analyzed by simulating Si tracker and calorimeter alternative configurations and detection materials, within missions’ volume, mass and power margins. The modulation polarimetric factor,
Q
, and the MDP were calculated for different polarized source types and for variable incidence angle measurement conditions. Finally, the polarimetric performances of both instruments was compared and analyzed.
Q
modulation factors obtained ranged between ~0.2 and ~0.4 in the 0.2–2.0 MeV band and MDP ~0.65% was estimated for a 100% polarized Crab type source, 1 Ms. observation time and 3
σ
significance.
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