Baseline design of the filters for the LAD detector on board LOFT

The Large Observatory for X-ray Timing (LOFT) was one of the M3 missions selected for the phase A study in the ESA's Cosmic Vision program. LOFT is designed to perform high-time-resolution X-ray observations of black holes and neutron stars. The main instrument on the LOFT payload is the Large Area Detector (LAD), a collimated experiment with a nominal effective area of ~10 m 2 @ 8 keV, and a spectral resolution of ~240 eV in the energy band 2-30 keV. These performances are achieved covering a large collecting area with more than 2000 large-area Silicon Drift Detectors (SDDs) each one coupled to a collimator based on lead-glass micro-channel plates. In order to reduce the thermal load onto the detectors, which are open to Sky, and to protect them from out of band radiation, optical-thermal filter will be mounted in front of the SDDs. Different options have been considered for the LAD filters for best compromise between high quantum efficiency and high mechanical robustness. We present the baseline design of the optical-thermal filters, show the nominal performances, and present preliminary test results performed during the phase A study.Comment: Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91446

Flight investigation of the effects of Apollo heat-shield singularities on ablator performance

Launch vehicle flight tests of effects of Apollo heat shield irregularities on ablative material performanc

Quantum Mechanics Another Way

Deformation quantization (sometimes called phase-space quantization) is a formulation of quantum mechanics that is not usually taught to undergraduates. It is formally quite similar to classical mechanics: ordinary functions on phase space take the place of operators, but the functions are multiplied in an exotic way, using the star product. Here we attempt a brief, pedagogical discussion of deformation quantization, that is suitable for inclusion in an undergraduate course.Comment: 14 pages, 3 figures, to be published in Eur. J. Phy

Profile of the most common complaints for five health professions in Australia

© 2019 AHHA. Objective: The aims of this study were to profile the most common complaints and to examine whether any demographic factors are associated with receiving a complaint for five health professions in Australia. Methods: A national cohort study was conducted for all complaints received for medicine, nursing/midwifery, dentistry, pharmacy and psychology from 1 July 2012 to 31 December 2013 (18 months). Data were collected from the Australian Health Practitioner Regulation Agency (AHPRA), the New South Wales (NSW) Health Professional Councils' Authority and the NSW Health Care Complaints Commission. The frequency and risk of complaints were summarised for the five professions and by demographic information. Results: There were 545 283 practitioners registered with AHPRA between 1 July 2012 and 31 December 2013, consisting of 20 935 dentists, 101 066 medical practitioners, 363 040 nurses/midwives, 28 370 pharmacists and 31 872 psychologists. During the study period there were 12 616 complaints, corresponding to an annual rate of 1.5 per 100 practitioners. Complaints were most common for doctors and dentists (5% per annum per practitioner) and least common for nurses/midwives (0.5% per annum per practitioner). Sex (P < 0.01), age (P < 0.01) and country of birth (P < 0.01) were all associated with risk of complaint. The most common complaints were clinical care (44% of all complaints), medication (10%) and health impairment of the practitioner (8%). Types of complaints varied by profession, sex and age. Conclusions: The risk of a complaint is low, but varies by profession and demographics. The types of complaints also vary by profession and demographics. Differences between professions is most likely driven by their different work tasks and work environments. What is already known on this subject?: Although complaints are summarised annually from state and national health regulators, no overall national summary of complaints across professions exists. Thus, it is difficult to examine which complaints are most common, how professions differ from each other or what factors may be associated with risk and type of complaint. Previous studies have primarily focused on a single profession, such as medicine, where, for example, the number of prior complaints, sex, doctor speciality and age have been found to be associated with recurrent complaints. What does this paper add?: This paper is the first of this kind to provide a national summary of all complaints from five of the most common health professions in Australia. We found that regardless of profession, men were at least twice as likely to have a complaint made against them than women. We also found that the types of complaint differed between men and women. There were similarities across professions for the most common types of complaints, but clear differences between professions were also noted. Not surprising, clinical care was typically the most common type of complaint for the five professions, but somewhat surprising was the inclusion of health impairment as one of the most common types of complaints. What are the implications for practitioners?: Identifying the most common complaints, and the factors associated with these, may assist practitioners to understand their risk(s) of complaint and could potentially assist educators and regulators develop education programs that help reduce complaints

High-z radio starbursts host obscured X-ray AGN

We use Virtual Observatory methods to investigate the association between radio and X-ray emission at high redshifts. Fifty-five of the 92 HDF(N) sources resolved by combining MERLIN+VLA data were detected by Chandra, of which 18 are hard enough and bright enough to be obscured AGN. The high-z population of microJy radio sources is dominated by starbursts an order of magnitude more active and more extended than any found at z<1 and at least a quarter of these simultaneously host highly X-ray-luminous obscured AGN.Comment: 4 pages, 2 figures, To appear in the proceedings of 'At the Edge of the Universe' (9-13 October 2006, Sintra, Portugal

Differential criterion of a bubble collapse in viscous liquids

The present work is devoted to a model of bubble collapse in a Newtonian viscous liquid caused by an initial bubble wall motion. The obtained bubble dynamics described by an analytic solution significantly depends on the liquid and bubble parameters. The theory gives two types of bubble behavior: collapse and viscous damping. This results in a general collapse condition proposed as the sufficient differential criterion. The suggested criterion is discussed and successfully applied to the analysis of the void and gas bubble collapses.Comment: 5 pages, 3 figure

The bends on a quantum waveguide and cross-products of Bessel functions

A detailed analysis of the wave-mode structure in a bend and its incorporation into a stable algorithm for calculation of the scattering matrix of the bend is presented. The calculations are based on the modal approach. The stability and precision of the algorithm is numerically and analytically analysed. The algorithm enables precise numerical calculations of scattering across the bend. The reflection is a purely quantum phenomenon and is discussed in more detail over a larger energy interval. The behaviour of the reflection is explained partially by a one-dimensional scattering model and heuristic calculations of the scattering matrix for narrow bends. In the same spirit we explain the numerical results for the Wigner-Smith delay time in the bend.Comment: 34 pages, 21 figure

Fantastic plastic? Experimental evaluation of polyurethane bone substitutes as proxies for human bone in trauma simulations

Recent years have seen steady improvements in the recognition and interpretation of violence related injuries in human skeletal remains. Such work has at times benefited from the involvement of biological anthropologists in forensic casework and has often relied upon comparison of documented examples with trauma observed in skeletal remains. In cases where no such example exists investigators must turn to experimentation. The selection of experimental samples is problematic as animal proxies may be too dissimilar to humans and human cadavers may be undesirable for a raft of reasons. The current article examines a third alternative in the form of polyurethane plates and spheres marketed as viable proxies for human bone in ballistic experiments. Through subjecting these samples to a range of impacts from both modern and archaic missile weapons it was established that such material generally responds similarly to bone on a broad, macroscopic scale but when examined in closer detail exhibits a range of dissimilarities that call for caution in extrapolating such results to real bone

Nitrogenase Complexes: Multiple Docking Sites for a Nucleotide Switch Protein

Adenosine triphosphate (ATP) hydrolysis in the nitrogenase complex controls the cycle of association and dissociation between the electron donor adenosine triphosphatase (ATPase) (Fe-protein) and its target catalytic protein (MoFe-protein), driving the reduction of dinitrogen into ammonia. Crystal structures in different nucleotide states have been determined that identify conformational changes in the nitrogenase complex during ATP turnover. These structures reveal distinct and mutually exclusive interaction sites on the MoFe-protein surface that are selectively populated, depending on the Fe-protein nucleotide state. A consequence of these different docking geometries is that the distance between redox cofactors, a critical determinant of the intermolecular electron transfer rate, is coupled to the nucleotide state. More generally, stabilization of distinct docking geometries by different nucleotide states, as seen for nitrogenase, could enable nucleotide hydrolysis to drive the relative motion of protein partners in molecular motors and other systems