Uncovering the geometry of the hot X-ray corona in the Seyfert galaxy NGC 4151 with IXPE

We present an X-ray spectropolarimetric analysis of the bright Seyfert galaxy NGC 4151. The source has been observed with the Imaging X-ray Polarimetry Explorer (IXPE) for 700 ks, complemented with simultaneous XMM–Newton (50 ks) and NuSTAR (100 ks) pointings. A polarization degree Π = 4.9 ± 1.1 per cent and angle Ψ = 86° ± 7° east of north (68 per cent confidence level) are measured in the 2–8 keV energy range. The spectropolarimetric analysis shows that the polarization could be entirely due to reflection. Given the low reflection flux in the IXPE band, this requires, however, a reflection with a very large (>38 per cent) polarization degree. Assuming more reasonable values, a polarization degree of the hot corona ranging from ∼4 to ∼8 per cent is found. The observed polarization degree excludes a ‘spherical’ lamppost geometry for the corona, suggesting instead a slab-like geometry, possibly a wedge, as determined via Monte Carlo simulations. This is further confirmed by the X-ray polarization angle, which coincides with the direction of the extended radio emission in this source, supposed to match the disc axis. NGC 4151 is the first active galactic nucleus with an X-ray polarization measure for the corona, illustrating the capabilities of X-ray polarimetry and IXPE in unveiling its geometry

The X-ray polarization of the Seyfert 1 galaxy IC 4329A

We present an X-ray spectro-polarimetric analysis of the bright Seyfert galaxy IC 4329A. The Imaging X-ray Polarimetry Explorer (IXPE) observed the source for ∼500 ks, supported by XMM–Newton (∼60 ks) and NuSTAR (∼80 ks) exposures. We detect polarization in the 2–8 keV band with 2.97σ confidence. We report a polarization degree of 3.3 ± 1.1 per cent and a polarization angle of 78° ± 10° (errors are 1σ confidence). The X-ray polarization is consistent with being aligned with the radio jet, albeit partially due to large uncertainties on the radio position angle. We jointly fit the spectra from the three observatories to constrain the presence of a relativistic reflection component. From this, we obtain constraints on the inclination angle to the inner disc (<39° at 99 per cent confidence) and the disc inner radius (<11 gravitational radii at 99 per cent confidence), although we note that modelling systematics in practice add to the quoted statistical error. Our spectropolarimetric modelling indicates that the 2–8 keV polarization is consistent with being dominated by emission directly observed from the X-ray corona, but the polarization of the reflection component is completely unconstrained. Our constraints on viewer inclination and polarization degree tentatively favour more asymmetric, possibly out-flowing, coronal geometries that produce more highly polarized emission, but the coronal geometry is unconstrained at the 3σ level

ICAR: endoscopic skull‐base surgery

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Evaluating the Psychometric Properties of the Maslach Burnout Inventory-Human Services Survey (MBI-HSS) among Italian Nurses: How Many Factors Must a Researcher Consider?

BACKGROUND:The Maslach Burnout Inventory (MBI) is the mainstream measure for burnout. However, its psychometric properties have been questioned, and alternative measurement models of the inventory have been suggested. AIMS:Different models for the number of items and factors of the MBI-HSS, the version of the Inventory for the Human Service sector, were tested in order to identify the most appropriate model for measuring burnout in Italy. METHODS:The study dataset consisted of a sample of 925 nurses. Ten alternative models of burnout were compared using confirmatory factor analysis. The psychometric properties of items and reliability of the MBI-HSS subscales were evaluated. RESULTS:Item malfunctioning may confound the MBI-HSS factor structure. The analysis confirmed the factorial structure of the MBI-HSS with a three-dimensional, 20-item assessment. CONCLUSIONS:The factorial structure underlying the MBI-HSS follows Maslach's definition when items are reduced from the original 22 to a 20-item set. Alternative models, either with fewer items or with an increased number of latent dimensions in the burnout structure, do not yield better results to justify redefining the item set or theoretically revising the syndrome construct

The contribution of pre-existing depression to the acute cognitive sequelae of mild traumatic brain injury

Primary objective: To determine the effect of pre-existing depression on the cognitive sequelae of mild traumatic brain injury ( mTBI) within 24 hours of injury. Research design: A 2 x 2 between-subjects design was used to examine the effect of depression and injury type on neuropsychological test performance. The independent variables were the injury type ( mTBI or control) and the presence of depression ( depressed or not depressed). Methods and procedures: Participants who had sustained mTBI ( 30 with depression, 30 without depression) within the previous 24 hours and control participants ( 19 with depression, 30 without depression) were assessed on the Digit Symbol Substitution Test ( DSS), Hopkins Verbal Learning Test ( HVLT) and the Speed of Comprehension Test. Results: Participants with mTBI performed worse than controls on the tests, particularly HVLT delayed recall and DSS total correct. Participants with depression did not perform worse than participants without depression. However, there was a significant univariate interaction for HVLT recognition, participants who had sustained mTBI and were classified in the depressed group exhibited worse recognition compared to mTBI participants without depression. Conclusions: The results indicate that depression may interact with mTBI to impair word recognition during the acute phase after a head injury