X-ray Absorption and Reflection in Active Galactic Nuclei

X-ray spectroscopy offers an opportunity to study the complex mixture of emitting and absorbing components in the circumnuclear regions of active galactic nuclei, and to learn about the accretion process that fuels AGN and the feedback of material to their host galaxies. We describe the spectral signatures that may be studied and review the X-ray spectra and spectral variability of active galaxies, concentrating on progress from recent Chandra, XMM-Newton and Suzaku data for local type 1 AGN. We describe the evidence for absorption covering a wide range of column densities, ionization and dynamics, and discuss the growing evidence for partial-covering absorption from data at energies > 10 keV. Such absorption can also explain the observed X-ray spectral curvature and variability in AGN at lower energies and is likely an important factor in shaping the observed properties of this class of source. Consideration of self-consistent models for local AGN indicates that X-ray spectra likely comprise a combination of absorption and reflection effects from material originating within a few light days of the black hole as well as on larger scales. It is likely that AGN X-ray spectra may be strongly affected by the presence of disk-wind outflows that are expected in systems with high accretion rates, and we describe models that attempt to predict the effects of radiative transfer through such winds, and discuss the prospects for new data to test and address these ideas.Comment: Accepted for publication in the Astronomy and Astrophysics Review. 58 pages, 9 figures. V2 has fixed an error in footnote

Emotional and interpersonal factors are most important for patient satisfaction with anaesthesia

BACKGROUND: Questionnaires to evaluate patient satisfaction with anaesthesia mainly consider physiological aspects. This study was performed to identify the items of value for patients having anaesthesia (pilot phase) and to validate the questionnaire built on these findings in a new group of inpatients. METHODS: In the pilot phase, 100 surgical patients were interviewed and asked whether each of the 23 items selected by a panel of providers was relevant (score 1) and to rank these from 1 (additional score 6) to 5 (additional score 2). The resulting 10-item final instrument was administered to 219 consecutive inpatients by interview, after recent anaesthesia, asking them how much of each item they received (item received) and the level of satisfaction with the same item, using Numerical Rating Scales (range 0-10). RESULTS: In the pilot phase, gender, age, education and surgery did not influence the score enough to change the first 10 rank-ordered items. The 219 patients subsequently studied did not differ from those missing the questionnaire administration. The patients aged less than 55 years showed lower satisfaction scores than those aged 55 years or more (P = 0.019). In all items, except 'feeling anxious/frightened', the item received was significantly associated with the satisfaction reported. 'Kindness/regard of caregivers' together with 'information given by anaesthetist' and 'feeling safe' predicted 47% of the variance in total patient satisfaction. CONCLUSIONS: Inpatients value highly those elements of care that pertain to emotional and interpersonal relationships

Damping properties of a SMA/GFRP composite beam

Shape memory alloys (SMA) besides shape memory and superelastic properties, are characterised by significant damping properties, especially during phase transformation and in the martensitic state. Combining these features with mechanical properties and light weight of glass fiber reinforced polymer (GFRP) allows the design of advanced composite materials suitable in many structural applications affected by vibration problems. A SMA sheet, after laser patterning, was introduced in a laminated composite between a thick GFRP core and two thin outer layers, with the aim of enhancing the damping capacity of a GFRP beam through passive vibration suppression. The selected SMA was a CuZnAl alloy sheet, obtained from an induction melted ingot, further hot and cold rolled down to 0.2 mm thickness. In order to enhance the interface adhesion between polymer and SMA and to optimally exploit the damping capacity of the sheets, different patterns of elliptical holes investigated.. Besides, the pattern design also allowed the amount of SMA metal introduced in the composite beam to be varied. A pulsed fiber laser source was used in order to realise the hole patterns on the SMA sheets. After the laser processing, the SMA sheets were heat treated in order to gain the desired shape memory properties. The transformation temperatures were checked by differential scanning calorimetry (DSC). The damping properties at room temperature were determined on full scale sheet, using a universal testing machine, with cyclic tensile tests at different deformation amplitudes. The temperature dependence was obtained on miniature samples (1mm wide, 25mm long) with a dynamical mechanical analyser (DMA). Damping properties, obtained from the described dynamic characterization of the CuZnAl sheets were used in conjunction with finite element method (FEM) analysis and modal strain energy (MSE) approach in order to calculate the laminated composite damping capacity. Beams of the laminated composite (25 mm wide, 5mm thick, 200 mm long), with different patterning schemes, were assembled and cured in autoclave. Experimental decay tests on the prototypes in their first flexural mode were performed and the damping properties of the advanced material as a function of the different patterning schemes were verified

Electron gas with polaronic effects: beyond the mean-field theory

The occurrence of polaronic behaviour in real solids is often accompanied by strong exchange and correlation effects in the electron gas besides being strongly entangled to the phononic degrees of freedom. Such effects can be relevant for the instability towards Wigner crystallization or charge density waves, or yet for the polaron role in high-T(C) superconductors and in manganites. The inclusion of exchange and correlation in the coupled electron-phonon system is thus highly desirable. In this work, we exploit the density functional theory and its time-dependent extension to construct an appropriate effective potential useful for studying the properties of interacting polarons. The validity and the possible developments of this approach are discussed, and future applications are proposed