Thermal evidence for the structural instability in Ni3 Al alloys

The thermal expansion coefficient (¿) and calorimetric data were obtained as a function of temperature in order to clarify some of the significant variations reported with regard to these values in the literature. Stoichiometric and off-stoichiometric compositions of Ni3Al alloys (with and without boron addition) were investigated. Dilatometric experiments were performed on all the alloys and the ¿ values were estimated over the temperature range from ambient to 1000°C. Two runs were made on each sample under different initial conditions and differences in ¿ values were noticed. The results were analysed based on our earlier X-ray diffraction results. Additional isothermal dilatometric tests were also carried out and a significant volume change was noticed (0.45% contraction) when the alloy quenched from 1000°C was heated to 600°C and held for a long duration. The calorimetric data were obtaindd over the same range of temperature and enthalpy changes, though less distinct, were noticed at around 360, 660 and 900°C. The variations seen further augment our earlier results on the instability of the L12 structure and the existence of a structural transformatio

A luminosity monitor for the A4 parity violation experiment at MAMI

A water Cherenkov luminosity monitor system with associated electronics has been developed for the A4 parity violation experiment at MAMI. The detector system measures the luminosity of the hydrogen target hit by the MAMI electron beam and monitors the stability of the liquid hydrogen target. Both is required for the precise study of the count rate asymmetries in the scattering of longitudinally polarized electrons on unpolarized protons. Any helicity correlated fluctuation of the target density leads to false asymmetries. The performance of the luminosity monitor, investigated in about 2000 hours with electron beam, and the results of its application in the A4 experiment are presented.Comment: 22 pages, 12 figures, submitted to NIM

Geometrical statistics of the vorticity vector and the strain rate tensor in rotating turbulence

We report results on the geometrical statistics of the vorticity vector obtained from experiments in electromagnetically forced rotating turbulence. A range of rotation rates $\Omega$ is considered, from non-rotating to rapidly rotating turbulence with a maximum background rotation rate of $\Omega=5$ rad/s (with Rossby number much smaller than unity). Typically, in our experiments ${\rm{Re}}_{\lambda}\approx 100$. The measurement volume is located in the centre of the fluid container above the bottom boundary layer, where the turbulent flow can be considered locally statistically isotropic and horizontally homogeneous for the non-rotating case, see van Bokhoven et al., Phys. Fluids 21, 096601 (2009). Based on the full set of velocity derivatives, measured in a Lagrangian way by 3D Particle Tracking Velocimetry, we have been able to quantify statistically the effect of system rotation on several flow properties. The experimental results show how the turbulence evolves from almost isotropic 3D turbulence ($\Omega\lesssim 0.2$ rad/s) to quasi-2D turbulence ($\Omega\approx 5.0$ rad/s) and how this is reflected by several statistical quantities. In particular, we have studied the orientation of the vorticity vector with respect to the three eigenvectors of the local strain rate tensor and with respect to the vortex stretching vector. Additionally, we have quantified the role of system rotation on the self-amplification terms of the enstrophy and strain rate equations and the direct contribution of the background rotation on these evolution equations. The main effect is the strong reduction of extreme events and related (strong) reduction of the skewness of PDFs of several quantities such as, for example, the intermediate eigenvalue of the strain rate tensor and the enstrophy self-amplification term.Comment: 17 pages, 6 figures, 3 table

Clinical problems with the performance of euthanasia and physician-assisted suicide in The Netherlands

BACKGROUND AND METHODS: The characteristics and frequency of clinical problems with the performance of euthanasia and physician-assisted suicide are uncertain. We analyzed data from two studies of euthanasia and physician-assisted suicide in The Netherlands (one conducted in 1990 and 1991 and the other in 1995 and 1996), with a total of 649 cases. We categorized clinical problems as technical problems, such as difficulty inserting an intravenous line; complications, such as myoclonus or vomiting; or problems with completion, such as a longer-than-expected interval between the administration of medications and death. RESULTS: In 114 cases, the physician's intention was to provide assistance with suicide, and in 535, the intention was to perform euthanasia. Problems of any type were more frequent in cases of assisted suicide than in cases of euthanasia. Complications occurred in 7 percent of cases of assisted suicide, and problems with completion (a longer-than-expected time to death, failure to induce coma, or induction of coma followed by awakening of the patient) occurred in 16 percent of the cases; complications and problems with completion occurred in 3 percent and 6 percent of cases of euthanasia, respectively. The physician decided to administer a letha

Physician-assisted death in psychiatric practice in the Netherlands

BACKGROUND: In 1994 the Dutch Supreme Court ruled that in exceptional instances, physician-assisted suicide might be justifiable for patients with unbearable mental suffering but no physical illness. We studied physician-assisted suicide and euthanasia in psychiatric practice in the Netherlands. METHODS: In 1996, we sent questionnaires to 673 Dutch psychiatrists - about half of all such specialists in the country - and received 552 responses from the 667 who met the study criteria (response rate, 83 percent). We estimated the annual frequencies of requests for physician-assisted suicide by psychiatrists and actual instances of assistance. RESULTS: Of the respondents, 205 (37 percent) had at least once received an explicit, persistent request for physician-assisted suicide and 12 had complied. We estimate there are 320 requests a year i

A new approach to evidence synthesis in traumatic brain injury: a living systematic review

Living systematic reviews (LSRs) are online summaries of health care research that are updated as new research becomes available. This new development in evidence synthesis is being trialled as part of the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) project. We will develop and sustain an international TBI knowledge community that maintains up-to-date, high quality LSRs of the current state of knowledge in the most important questions in TBI. Automatic search updates will be run three-monthly, and newly identified studies incorporated into the review. Review teams will seek to publish journal updates at regular intervals, with abridged updates available more frequently online. Future project stages include the integration of LSR and other study findings into "living" clinical practice guidance. It is hoped these efforts will go some way to bridging current temporal disconnects between evidence, guidelines, and practice in TBI.Development and application of statistical models for medical scientific researc

Police ethics and integrity: Can a new code overturn the blue code?

This paper analyses police officer perspectives on the seriousness of potential misconduct or unethical behaviour, and the factors that might shape whether they would report their colleagues' misdemeanours. It compares responses from police officers in UK three forces, looking at potentially corrupt behaviours described in a series of scenarios. The discussion includes why some types of misdemeanour seem more likely to be reported and the potential effects of a newly introduced formal Code of Ethics. In terms of differences between ranks and roles, and different responses from different services, the study suggests that the way police culture operates is significant and needs to be more widely addressed. The study used scenario based questionnaires to elicit views about the seriousness of certain police behaviours and to ask whether officers would report colleagues' misdemeanours. It develops a previous survey by one of the authors which conducted a similar survey published in 2005. Using the same questionnaire the new study examined a larger and more diverse sample of serving officers (n=520). This new study compares responses from police officers in UK three forces, geographically distributed across the country and have differing characteristics in terms of size, rurality, population density and policing priorities