Mental defeat is associated with suicide intent in patients with chronic pain

Objective: Mental defeat has been implicated in precipitating suicide with effects not explained by depression. It has also been found to be elevated in people who are most distressed and disabled by chronic pain. This study examined the role of mental defeat in predicting suicide intent among chronic pain patients and compared the predictive value of mental defeat with other established pain and psychological constructs. Methods: Sixty-two chronic pain patients attended a semi-structured interview to assess pain characteristics and suicidality (present and worst-ever) and completed self-report measures of anxiety, depression, hopelessness, self-efficacy, pain catastrophising and mental defeat. Results: A total of 22.6% of people reported a history of suicide attempt (1 attempt=12.9%;≥2 attempts=9.7%). The wish to die was reportedly moderate to strong for 63.3% of those who attempted suicide. No significant correlations were found for hopelessness and self-efficacy with suicide intent in this sample. Hierarchical regression analyses suggested that pain intensity was a significant predictor of worst-ever suicidal intent (R=0.11), and mental defeat significantly improved the prediction even when the effect of pain intensity was accounted for (RΔ=0.12). Anxiety, depression and pain catastrophising were significant correlates of suicide intent, but they did not add to the prediction of worst-ever suicide intent after the effect of pain intensity was controlled for. Discussion: Mental defeat may be a key indicator for heightened suicide risk. Therapeutic interventions targeting mental defeat offer a novel avenue for reducing suicide risk in chronic pain patients

A layered edge-on circumstellar disk around HK Tau B

We present the first high angular resolution 1.4mm and 2.7mm continuum maps of the T Tauri binary system HK Tau obtained with the Plateau de Bure Interferometer. The contributions of both components are well disentangled at 1.4mm and the star previously known to host an edge-on circumstellar disk, HK Tau B, is elongated along the disk's major axis. The optically bright primary dominates the thermal emission from the system at both wavelengths, confirming that it also has its own circumstellar disk. Its non-detection in scattered light images indicates that the two disks in this binary system are not parallel. Our data further indicate that the circumprimary disk is probably significantly smaller than the circumsecondary disk. We model the millimeter thermal emission from the circumstellar disk surrounding HK Tau B. We show that the disk mass derived from scattered light images cannot reproduce the 1.4mm emission using opacities of the same population of submicron dust grains. However, grain growth alone cannot match all the observed properties of this disk. We propose that this disk contains three separate layers: two thin outer surfaces which contain dust grains that are very similar to those of the ISM, and a disk interior which is relatively massive and/or has experienced limited grain growth with the largest grains significantly smaller than 1mm. Such a structure could naturally result from dust settling in a protoplanetary disk.Comment: Accepted fopr publication in A&A, 8 pages, 1 embedded figur

General relativistic radiative transfer: formulation and emission from structured tori around black holes

We construct a general relativistic radiative transfer (RT) formulation, applicable to particles with or without mass in astrophysical settings. Derived from first principles, the formulation is manifestly covariant. Absorption and emission, as well as relativistic, geometrical and optical depth effects are treated self-consistently. The RT formulation can handle 3D geometrical settings and structured objects with variations and gradients in the optical depths across the objects and along the line-of-sight. The presence of mass causes the intensity variation along the particle bundle ray to be reduced by an aberration factor. We apply the formulation and demonstrate RT calculations for emission from accretion tori around rotating black holes, considering two cases: idealised optically thick tori that have a sharply defined emission boundary surface, and structured tori that allow variations in the absorption coefficient and emissivity within the tori. Intensity images and emission spectra of these tori are calculated. Geometrical effects, such as lensing-induced self-occulation and multiple-image contribution are far more significant in accretion tori than geometrically thin accretion disks. Optically thin accretion tori emission line profiles are distinguishable from the profiles of lines from optically thick accretion tori and optically thick geometrically thin accretion disks. Line profiles of optically thin accretion tori have a weaker dependence on viewing inclination angle than those of the optically thick accretion tori or accretion disks, especially at high viewing inclination angles. Limb effects are present in accretion tori with finite optical depths. Finally, in accretion flows onto relativistic compact objects, gravitationally induced line resonance can occur. This resonance occurs easily in 3D flows, but not in 2D flows, such as a thin accretion disk around a black hole.Comment: 13 pages, 10 figures, Accepted for publication in Astronomy and Astrophysic

Molecular hydrogen emission in NGC 7027

The spatial distribution of the emission in the v = 1-0 S(1) line of H2 in the planetary nebula NGC 7027 is presented. The excited H2 molecules do not fill the same volume as the ionized gas and most likely reside near the outer edge of the nebula. The spatial resolution of the data, 5 arcsec, is insufficient to define the location of the molecules precisely. An upper limit to the strength of the v = 2-1 S(1) line is given; it is low enough to preclude simple ultraviolet fluorescence as the source of excitation. A simple shock model can fit the line ratio data, however, and there is enough energy in the expanding nebula to sustain such a shock. A rough estimate of 1 M_⊙ to 4 M_⊙ for the mass in the molecular cloud surrounding NGC 7027 is derived

Setting Priorities for Space Research: Opportunities and Imperatives

This report represents the first phase of a study by a task group convened by the Space Studies Board to ascertain whether it should attempt to develop a methodology for recommending priorities among the various initiatives in space research (that is, scientific activities concerned with phenomena in space or utilizing observations from space). The report argues that such priority statements by the space research community are both necessary and desirable and would contribute to the formulation and implementation of public policy. The report advocates the establishment of priorities to enhance effective management of the nation's scientific research program in space. It argues that scientific objectives and purposes should determine how and under what circumstances scientific research should be done. The report does not take a position on the controversy between advocates of manned space exploration and those who favor the exclusive use of unmanned space vehicles. Nor does the report address questions about the value or appropriateness of Space Station Freedom or proposals to establish a permanent manned Moon base or to undertake a manned mission to Mars. These issues lie beyond the charge to the task group

Evolution of optically faint AGN from COMBO-17 and GEMS

We have mapped the AGN luminosity function and its evolution between z=1 and z=5 down to apparent magnitudes of $R<24$. Within the GEMS project we have analysed HST-ACS images of many AGN in the Extended Chandra Deep Field South, enabling us to assess the evolution of AGN host galaxy properties with cosmic time.Comment: to appear in proceedings 'Multiwavelength AGN Surveys', Cozumel 200

Line emission from optically thick relativistic accretion tori

We calculate line emission from relativistic accretion tori around Kerr black holes and investigate how the line profiles depend on the viewing inclination, spin of the central black hole, parameters describing the shape of the tori, and spatial distribution of line emissivity on the torus surface. We also compare the lines with those from thin accretion disks. Our calculations show that lines from tori and lines from thin disks share several common features. In particular, at low and moderate viewing inclination angles they both have asymmetric double-peaked profiles with a tall, sharp blue peak and a shorter red peak which has an extensive red wing. At high viewing inclination angles they both have very broad, asymmetric lines which can be roughly considered single-peaked. Torus and disk lines may show very different red and blue line wings, but the differences are due to the models for relativistic tori and disks having differing inner boundary radii. Self-eclipse and lensing play some role in shaping the torus lines, but they are effective only at high inclination angles. If inner and outer radii of an accretion torus are the same as those of an accretion disk, their line profiles show substantial differences only when inclination angles are close to 90 degrees, and those differences manifest mostly at the central regions of the lines instead of the wings.Comment: 14 pages, 17 figures. Accepted to A&