Mock-Gaussian Behaviour for Linear Statistics of Classical Compact Groups

We consider the scaling limit of linear statistics for eigenphases of a matrix taken from one of the classical compact groups. We compute their moments and find that the first few moments are Gaussian, whereas the limiting distribution is not. The precise number of Gaussian moments depends upon the particular statistic considered

Raising the Dead: Clues to Type Ia Supernova Physics from the Remnant 0509-67.5

We present Chandra X-ray observations of the young supernova remnant (SNR) 0509-67.5 in the Large Magellanic Cloud (LMC), believed to be the product of a Type Ia supernova (SN Ia). The remnant is very round in shape, with a distinct clumpy shell-like structure. Our Chandra data reveal the remnant to be rich in silicon, sulfur, and iron. The yields of our fits to the global spectrum confirm that 0509-67.5 is the remnant of an SN Ia and show a clear preference for delayed detonation explosion models for SNe Ia. We study the spectrum of the single brightest isolated knot in the remnant and find that it is enhanced in iron by a factor of roughly two relative to the global remnant abundances. This feature, along with similar knots seen in Tycho's SNR, argues for the presence of modest small-scale composition inhomogeneities in SNe Ia. The presence of both Si and Fe, with abundance ratios that vary from knot to knot, indicates that these came from the transition region between the Si- and Fe-rich zones in the exploded star, possibly as a result of energy input to the ejecta at late times due to the radioactive decay of 56Ni and 56Co. Two cases for the continuum emission from the global spectrum were modeled: one where the continuum is dominated by hydrogen thermal bremsstrahlung radiation; another where the continuum arises from non-thermal synchrotron radiation. The former case requires a relatively large value for the ambient density (~1 cm^-3). Another estimate of the ambient density comes from using the shell structure of the remnant in the context of dynamical models. This requires a much lower value for the density (<0.05 cm^-3) which is more consistent with other evidence known about 0509-67.5. We therefore conclude that the bulk of the continuum emission from 0509-67.5 has a non-thermal origin.Comment: 34 pages, 9 figures (1 color), accepted to ApJ (10 June 2004 issue); correction made to calculation of magnetic field, small sentence change

Training healthcare assistants working in adult acute inpatient wards in Psychological First Aid: An implementation and evaluation study.

WHAT IS KNOWN ON THE SUBJECT: Healthcare assistants are untrained and unregistered frontline staff but are expected to be proactive in preventing and responding to 'untoward' incidents quickly and efficiently when working within adult acute inpatient psychiatric settings. Healthcare assistants should be trained to provide enhanced care to service users residing in acute psychiatric settings. To date, a training programme in Psychological First Aid has not been expended in such a setting with nonregistered staff. WHAT THE PAPER ADDS TO EXISTING KNOWLEDGE: The study demonstrates that training healthcare assistants in Psychological First Aid is useful in improving their confidence in caring for service users, therapeutic engagement with service users and ward culture in general. WHAT ARE THE IMPLICATIONS FOR PRACTICE: A training programme in Psychological First Aid for healthcare assistants to enhance ward culture can be implemented in different practice environments. Psychological First Aid is harmonious with nursing values and provides healthcare assistants with a relevant, useful and easily understood toolkit to apply in acute psychiatric settings. ABSTRACT: Introduction Healthcare assistants working within adult acute inpatient psychiatric settings are untrained and unregistered, however, they can contribute to quality service if they receive some training. Psychological First Aid training has never been expended in these settings, so this study intends to fill this gap in the existing evidence with this category of healthcare personnel. Aim The aim of this study was to introduce and evaluate first aid training for healthcare assistants. Method A pre/post design was adopted to gather data using questionnaires and interviews. The groups of participants included 16 healthcare assistants trained in Psychological First Aid, a sample of service users and four ward managers. Results Post-training, (a) healthcare assistants and service users ranked the therapeutic milieu of the ward more favourably, (b) the self-efficacy of the healthcare assistants increased, and the number of 'untoward' incidents decreased, and (c) health care assistants' confidence in their skills was high. The ward manager interviews post-training revealed four themes: (a) staff utilization of new skills and renewed enthusiasm, (b) calmer atmosphere on the ward and staff togetherness, (c) confidence and reflection on practice and (d) therapeutic engagement. Discussion Training healthcare assistants is useful in improving staff confidence, therapeutic engagement with service users and ward culture in general. Implications for practice Techniques and skills learnt are relevant and useful to healthcare assistants and provide an easily understood toolkit that is harmonious with nursing values. If executed correctly, the training can enhance practice and care outcomes and the overall service user experience

A search for X-ray polarization in cosmic X-ray sources

Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission

Exploring the Physics of Type Ia Supernovae Through the X-ray Spectra of their Remnants

We present the results of an ongoing project to use the X-ray observations of Type Ia Supernova Remnants to constrain the physical processes involved in Type Ia Supernova explosions. We use the Tycho Supernova Remnant (SN 1572) as a benchmark case, comparing its observed spectrum with models for the X-ray emission from the shocked ejecta generated from different kinds of Type Ia explosions. Both the integrated spectrum of Tycho and the spatial distribution of the Fe and Si emission in the remnant are well reproduced by delayed detonation models with stratified ejecta. All the other Type Ia explosion models fail, including well-mixed deflagrations calculated in three dimensions.Comment: 5 pages, 3 figures, to appear in the proceedings of the "Stellar end products" workshop, 13-15 April 2005, Granada, Spain, ed. M.A. Perez-Torres, Vol. 77 (Jan 2006) of MmSA

Elemental abundances of the supernova remnant G292.0+1.8: evidence for a massive progenitor

We present a comprehensive nonequilibrium ionization (NEI) analysis of X-ray spectral data from the Einstein Observatory and EXOSAT for the supernova remnant G292.0+1.8. The spectra are well described by a single-temperature, single-timescale NEI model with kT=1.64+0.29−0.19 keV and net=(5.55+1.2−1.12×1010 cm−3s, which establishes that this remnant is indeed young and in the ionizing phase of evolution of its X-ray spectrum. We determine the abundances of the elements O, Ne, Mg, Si, S, Ar, and Fe and examine their variation over the allowed range of column density, kT, and net. Numerical calculations of the nucleosynthesis expected for a 25 solar mass progenitor agree best with the fitted abundances; in fact the minimum rms percent difference between this model and the derived abundances is only 15%. From the fitted emission measure and a simple geometric model of the remnant we estimate the mass of X-ray-emitting plasma to be 9.3+1.19−6.2 solar mass, for an assumed distance of 4.8±1.6 kpc. Additional errors on this mass estimate, from clumping of the ejecta, for example, may be substantial. No evidence was found for a difference in the thermodynamic state of the plasma as a function of elemental composition based on analysis of the individual ionization timescales of the various species. In this sense then, G292.0+1.8 resembles the remnant Cas A (another product of a massive star supernova), while it is different from the remnants of SN 1572 (Tycho) and SN 1006, both of which are believed to be from Type Ia supernovae