ROSAT and BeppoSAX evidence of soft X-ray excess emission in the Shapley supercluster: A3571, A3558, A3560 and A3562

Excess soft X-ray emission in clusters of galaxies has so far been detected for sources that lie along lines-of-sight to very low Galactic HI column density (such as Coma, A1795, A2199 and Virgo, N_H 0.9-2.0 10^{20} cm-2). We show that the cluster soft excess emission can be investigated even at higher N_H, which provides an opportunity for investigating soft X-ray emission characteristics among a large number of clusters. The ROSAT PSPC analysis of some members of the Shapley concentration (A3571, A3558, A3560 and A3562, at N_H 4-4.5 10^{20} cm-2) bears evidence for excess emission in the 1/4 keV band. We were able to confirm the finding for the case of A3571 by a pointed SAX observation. Within the current sample the soft X-ray flux is again found to be consistently above the level expected from a hot virialized plasma. The data quality is however insufficient to enable a discrimination between alternative models of the excess low energy flux.Comment: ApJL in press, 5 figure

An improved method of supercharged transposed latissimus dorsi flap with the skin paddle for the management of a complicated lumbosacral defect

OBJECTIVE: Treatment of nonhealing wounds of lower back often poses a powerful challenge. We present one of the first report of treatment of a lumbosacral defect with a supercharged latissimus dorsi flap with the skin paddle. CASE REPORT: We report a case of a 59 yearold man with myeloma of the sacral spine who underwent radiotherapy and chemotherapy and subsequently, laminectomies and placement of hardware for ongoing paresis and spine instability. Then, he developed an open wound and osteomyelitis of the spine with culture positive tuberculous granulomas. After multiple surgical debridement, he presented to our service and was treated with a single stage debridement followed by the performance of a latissimus dorsi musculocutaneous flap based on paraspinal perforators and supercharged. RESULTS: This solution, allowed for augmentation of blood flow to the muscle with the inferior gluteal artery, provided coverage of the defect resistant to the pressure, and simplified post-operative management of the patient. CONCLUSIONS: Alternative treatment options, including free tissue transfer, posed difficulties in finding suitable recipient vessels near the defect, in inserting the flap so as to restore its original length without compromising blood flow, and in postoperative care of the patient. Treatment of a lumbosacral defect with a supercharged latissimus dorsi flap with the skin paddle may represent a milestone procedure for complicated lower spine wounds

Analysis and control of geometrically nonlinear responses of piezoelectric FG porous plates with graphene platelets reinforcement using B\'ezier extraction

In this study, we propose an effective numerical approach to analyse and control geometrically nonlinear responses for the functionally graded (FG) porous plates reinforced by graphene platelets (GPLs) integrated with piezoelectric layers. The basis idea is to use isogeometric analysis (IGA) based on the B\'ezier extraction and the $C^0$-type higher-order shear deformation theory ($C^0$-HSDT). By applying the B\'ezier extraction, the original Non-Uniform Rational B-Spline (NURBS) control meshes can be transformed into the B\'ezier elements which allow us to inherit the standard numerical procedure like the finite element method (FEM). The mechanical displacement field is approximated based on the $C^0$-HSDT whilst the electric potential is assumed to be a linear function through the thickness of each piezoelectric sublayer. The FG plate contains the internal pores and GPLs dispersed in the metal matrix either uniformly or non-uniformly according to various different patterns along the thickness of plate. In addition, to control dynamic responses, two piezoelectric layers are perfectly bonded on the top and bottom surfaces of the FG plate. The geometrically nonlinear equations are solved by the Newton-Raphson iterative procedure and the Newmark's time integration scheme. The influences of the porosity coefficients, weight fractions of GPLs as well as the external electrical voltage on the geometrically nonlinear behaviours of the plates with different porosity distributions and GPL dispersion patterns are evidently investigated through numerical examples. Then, a constant displacement and velocity feedback control approaches are adopted to active control the geometrically nonlinear static as well as the dynamic responses of the FG porous plates, where the effect of the structural damping is considered, based on a closed-loop control with piezoelectric sensors and actuators.Comment: 39 pages, 20 figure

Thermal and non-thermal nature of the soft excess emission from Sersic 159-03 observed with XMM-Newton

Several nearby clusters exhibit an excess of soft X-ray radiation which cannot be attributed to the hot virialized intra-cluster medium. There is no consensus to date on the origin of the excess emission: it could be either of thermal origin, or due to an inverse Compton scattering of the cosmic microwave background. Using high resolution XMM-Newton data of Sersic 159-03 we first show that strong soft excess emission is detected out to a radial distance of 0.9 Mpc. The data are interpreted using the two viable models available, i.e., by invoking a warm reservoir of thermal gas, or relativistic electrons which are part of a cosmic ray population. The thermal interpretation of the excess emission, slightly favored by the goodness-of-fit analysis, indicates that the warm gas responsible for the emission is high in mass and low in metallicity.Comment: ApJ in pres

High- and low energy nonthermal X-ray emission from the cluster of galaxies A 2199

We report the detection of both soft and hard excess X-ray emission in the cluster of galaxies A 2199, based upon spatially resolved spectroscopy with data from the BeppoSAX, EUVE and ROSAT missions. The excess emission is visible at radii larger than 300 kpc and increases in strength relative to the isothermal component. The total 0.1-100 keV luminosity of this component is 15 % of the cluster luminosity, but it dominates the cluster luminosity at high and low energies. We argue that the most plausible interpretation of the excess emission is an inverse Compton interaction between the cosmic microwave background and relativistic electrons in the cluster. The observed spatial distribution of the non-thermal component implies that there is a large halo of cosmic ray electrons between 0.5-1.5 Mpc surrounding the cluster core. The prominent existence of this component has cosmological implications, as it is significantly changing our picture of a clusters's particle acceleration history, dynamics between the thermal and relativistic media, and total mass budgets.Comment: Accepted for publication in Astrophysical Journal, Letter

The importance of stakeholders in scoping risk assessments—Lessons from low-carbon transitions

Identifying the risks that could impact a low-carbon transition is a prerequisite to assessing and managing these risks. We systematically characterise risks associated with decarbonisation pathways in fifteen case studies conducted in twelve countries around the world. We find that stakeholders from business, government, NGOs, and others supplied some 40 % of these risk inputs, significantly widening the scope of risks considered by academics and experts. Overall, experts and academics consider more economic risks and assess these with quantitative methods and models, while other stakeholders consider political risks more. To avoid losing sight of risks that cannot be easily quantified and modelled, including some economic risks, impact assessment modelling should be complemented with qualitative research and active stakeholder engagement. A systematic risk elicitation facilitates communication with stakeholders, enables better risk mitigation, and increases the chance of a sustainable transition

Non-thermal Origin of the EUV and Soft X-rays from the Coma Cluster - Cosmic Rays in Equipartition with the Thermal Medium

The role of cosmic rays (CR) in the formation and evolution of clusters of galaxies has been much debated. It may well be related to other fundamental questions, such as the mechanism which heats and virializes the intracluster medium (ICM), and the frequency at which the ICM is shocked. There is now compelling evidence both from the cluster soft excess (CSE) and the `hard-tail' emissions at energies above 10 keV, that many clusters are luminous sources of inverse-Compton (IC) emission. This is the first direct measurement of cluster CR: the technique is free from our uncertainties in the ICM magnetic field, and is not limited to the small subset of clusters which exhibit radio halos. The CSE emitting electrons fall within a crucial decade of energy where they have the least spectral evolution, and where most of the CR pressure resides. However their survival times do not date them back to the relic CR population. By using the CSE data of the Coma cluster, we demonstrate that the CR are energetically as important as the thermal ICM: the two components are in pressure equiparition. Thus, contrary to previous expectations, CR are a dominant component of the ICM, and their origin and effects should be explored. The best-fit CR spectral index is in agreement with the Galactic value.Comment: ApJ accepted; 10 pages LaTeX; 2 figures and 1 table in PostScrip

Metal-rich multi-phase gas in M87: AGN-driven metal transport, magnetic-field supported multi-temperature gas, and constraints on non-thermal emission observed with XMM-Newton

We use deep (~120 ks) XMM-Newton data of the M87 halo to analyze its spatially resolved temperature structure and chemical composition. We focus particularly on the regions of enhanced X-ray brightness associated with the inner radio lobes, which are known not to be described very well by single-temperature spectral models. Compared to a simple two-temperature fit, we obtain a better and more physical description of the spectra using a model that involves a continuous range of temperatures in each spatial bin. The range of temperatures of the multiphase gas spans ~0.6-3.2 keV. Such a multiphase structure is only possible if thermal conduction is suppressed by magnetic fields. In the multi-temperature regions, we find a correlation between the amount of gas cooler than the surrounding X-ray plasma and the metallicity, and conclude that the cool gas is more metal-rich than the ambient halo. We estimate the average Fe abundance of the cool gas to ~2.2 solar. Our results thus point toward the key role of the active galactic nucleus (AGN) in transporting heavy elements into the intracluster medium. The abundance ratios of O/Si/S/Fe in and outside the X-ray arms are similar, indicating that the dominant fraction of metals in the gas halo was uplifted by AGN outbursts relatively recently compared to the age of M87. Our estimate for the mass of the cool gas is 5e8 M_sun, which probably stems from a mixture of ICM, stellar mass loss, and Type Ia supernova products. ~30-110 Myr are required to produce the observed metals in the cool gas. Finally, we put upper limits on possible non-thermal X-ray emission from M87 and, combining it with the 90 cm radio maps, we put lower limits of around ~0.5-1.0 muG on the magnetic field strength.Comment: 18 pages, accepted for publication in A&A. Some significant changes following the referee repor

Re-observing the EUV emission from Abell 2199: in-situ measurement of background distribution by offset pointing

The EUV excess emission from the clusters A2199 and A1795 remains an unexplained astrophysical phenomenon. There has been many unsuccessful attempts to `trivialize' the findings. In this Letter we present direct evidence to prove that the most recent of such attempts, which attributes the detected signals to a background non-uniformity effect, is likewise excluded. We address the issue by a re-observation of A2199 which features a new filter orientation, usage of a more sensitive part of the detector and, crucially, includes a background pointing at $\sim$ 2$^o$ offset - the first {\it in situ} measurement of its kind. We demonstrate quantitatively two facts: (a) the offset pointing provides an accurate background template for the cluster observation, while (b) data from other blank fields do not. We then performed point-to-point subtraction of the {\it in situ} background from the cluster field, with appropriate propagation of errors. The resulting cluster radial profile is consistent with that obtained by our original method of subtracting a flat asymptotic background. The emission now extends to a radius of 20 arcmin; it confirms the rising prominence of EUV excess beyond $\sim$ 5 arcmin as previously reported.Comment: 11 pages, 9 figures (1 color), ApJL in press; minor changes in the abstrac