We report spectro-polarimetric results of an observational campaign of the bright neutron star low-mass X-ray binary Cyg X-2 simultaneously observed by IXPE, NICER and INTEGRAL. Consistently with ...previous results, the broad-band spectrum is characterized by a lower-energy component, attributed to the accretion disc with \(kT_{\rm in} \approx\) 1 keV, plus unsaturated Comptonization in thermal plasma with temperature \(kT_{\rm e} = 3\) keV and optical depth \(\tau \approx 4\), assuming a slab geometry. We measure the polarization degree in the 2-8 keV band \(P=1.8 \pm 0.3\) per cent and polarization angle \(\phi = 140^{\circ} \pm 4^{\circ}\), consistent with the previous X-ray polarimetric measurements by OSO-8 as well as with the direction of the radio jet which was earlier observed from the source. While polarization of the disc spectral component is poorly constrained with the IXPE data, the Comptonized emission has a polarization degree \(P =4.0 \pm 0.7\) per cent and a polarization angle aligned with the radio jet. Our results strongly favour a spreading layer at the neutron star surface as the main source of the polarization signal. However, we cannot exclude a significant contribution from reflection off the accretion disc, as indicated by the presence of the iron fluorescence line.
We report on the Imaging X-ray Polarimetry Explorer (IXPE) observation of the closest and X-ray brightest Compton-thick active galactic nucleus (AGN), the Circinus galaxy. We find the source to be ...significantly polarized in the 2--6 keV band. From previous studies, the X-ray spectrum is known to be dominated by reflection components, both neutral (torus) and ionized (ionization cones). Our analysis indicates that the polarization degree is \(28 \pm 7\) per cent (at 68 per cent confidence level) for the neutral reflector, with a polarization angle of \(18{\deg} \pm 5{\deg}\), roughly perpendicular to the radio jet. The polarization of the ionized reflection is unconstrained. A comparison with Monte Carlo simulations of the polarization expected from the torus shows that the neutral reflector is consistent with being an equatorial torus with a half-opening angle of 45{\deg}-55{\deg}. This is the first X-ray polarization detection in a Seyfert galaxy, demonstrating the power of X-ray polarimetry in probing the geometry of the circumnuclear regions of AGNs, and confirming the basic predictions of standard Unification Models.
The space- and time-dependent response of many-body quantum systems is the most informative aspect of their emergent behaviour. The dynamical structure factor, experimentally measurable using neutron ...scattering, can map this response in wavevector and energy with great detail, allowing theories to be quantitatively tested to high accuracy. Here, we present a comparison between neutron scattering measurements on the one-dimensional spin-1/2 Heisenberg antiferromagnet KCuF3, and recent state-of-the-art theoretical methods based on integrability and density matrix renormalization group simulations. The unprecedented quantitative agreement shows that precise descriptions of strongly correlated states at all distance, time and temperature scales are now possible, and highlights the need to apply these novel techniques to other problems in low-dimensional magnetism.
To determine the prevalence of hip problems in the population aged 55+, a postal questionnaire was sent to a multistage stratified random sample of residents of a health district with an over-55 ...population of 210,000. An initial four page postal questionnaire produced an 86% response rate from 18,827 eligible cases. A subsequent detailed questionnaire (with a response rate of 78%) then determined the prevalence of severe pain and severe disability amongst those with hip problems. The prevalence of those with existing hip replacements is estimated at 32.1/1000 (95% CI 29.5-34.9). An estimated 13.5/1000 (95% CI 12.4-14.7/1000) displayed levels of pain and disability consistent with a current need to consider arthroplasty. In addition, it appears that the over 75s are less likely to have access to appropriate surgery. Unless health authorities and, increasingly, general practitioners consider purchasing more hip replacements, the prevalence pool of those who could benefit will inexorably rise.
We report on the first observation of a radio-quiet Active Galactic Nucleus (AGN) using polarized X-rays: the Seyfert 1.9 galaxy MCG-05-23-16. This source was pointed with the Imaging X-ray ...Polarimetry Explorer (IXPE) starting on May 14, 2022 for a net observing time of 486 ks, simultaneously with XMM-Newton (58 ks) and NuSTAR (83 ks). A polarization degree smaller than \(\Pi<4.7\%\) (at the 99% c.l.) is derived in the 2-8 keV energy range, where emission is dominated by the primary component ascribed to the hot corona. The broad-band spectrum, inferred from a simultaneous fit to the IXPE, NuSTAR, and XMM-Newton data, is well reproduced by a power law with photon index \(\Gamma=1.85\pm0.01\) and a high-energy cutoff \(E_{\rm C}=120\pm15\) keV. A comparison with Monte Carlo simulations shows that a lamp-post and a conical geometry of the corona are consistent with the observed upper limit, a slab geometry is allowed only if the inclination angle of the system is less than 50\(^{\circ}\).
For many years, the Stanford Health Assessment Questionnaire (HAQ) has provided an effective measure of disability. Recently, some debate has emerged about whether or not the HAQ is an "ordinal' or ..."interval' scale. The opportunity to test its level of measurement arose when the scale was applied in a community survey which undertook a two-stage random sample using postal questionnaires to ascertain the health care needs of those with arthritis. The HAQ data are fitted to the Rasch model which tests for the presence of certain desirable characteristics of measurement, e.g. unidimensionality. The fit of the data to the model for those self-reporting rheumatoid arthritis (RA) was adequate. The transformed HAQ score, derived from the Rasch analysis, is compared with the ordinary HAQ (raw) score. This shows that, for those with RA, incremental units of the raw score at the margins of the scale reflect an increasing level of (dis)ability compared to similar units in the centre of the scale. Thus, the traditional HAQ score (range 0-3) is an ordinal score. The findings also indicate that scoring all 20 items may lead to greater sensitivity. Questions are also raised about the construct validity for those with other types of arthritis. For osteoarthrosis, the grip item does not appear to belong to the same underlying construct as the other items.
This paper provides a clinical practice overview of the challenges that can arise when working with dangerous and severe personality-disordered patients in a high secure hospital. Poor engagement and ...treatment readiness, mistrust, paranoia and dominant interpersonal styles are all clinical features that affect treatment delivery. The paper discusses the impact of these features, and suggests how clinicians can engage effectively with individuals who have personality disorders in regard to therapy in general.
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