The Manchester occulting mask imager (MOMI) - first results on the environment of P Cygni

The design and first use of the Manchester occulting mask imager (MOMI) is described. This device, when combined with the Cassegrain or Ritchey-Chretien foci of large telescopes, is dedicated to the imagery of faint line emission regions around bright central sources. Initial observations, with MOMI on the Nordic Optical telescope (NOT), of the V=4.8 mag P~Cygni environment, have revealed a $\geq$~5~arcmin long [NII] 6584A emitting filament projecting from the outer nebular shell of this luminous blue variable (LBV) star. The presence of a mono-polar lobe older than both the inner (22 arcsec diameter) and outer (1.6 arcmin diameter) shells is suggested.Comment: 4 pages, 4 figures, accepted MNRAS 1998 June 1

The integrated motivational–volitional model of suicidal behaviour

Suicide is a major public health concern accounting for 800 000 deaths globally each year. Although there have been many advances in understanding suicide risk in recent decades, our ability to predict suicide is no better now than it was 50 years ago. There are many potential explanations for this lack of progress, but the absence, until recently, of comprehensive theoretical models that predict the emergence of suicidal ideation distinct from the transition between suicidal ideation and suicide attempts/suicide is key to this lack of progress. The current article presents the integrated motivational–volitional (IMV) model of suicidal behaviour, one such theoretical model. We propose that defeat and entrapment drive the emergence of suicidal ideation and that a group of factors, entitled volitional moderators (VMs), govern the transition from suicidal ideation to suicidal behaviour. According to the IMV model, VMs include access to the means of suicide, exposure to suicidal behaviour, capability for suicide (fearlessness about death and increased physical pain tolerance), planning, impulsivity, mental imagery and past suicidal behaviour. In this article, we describe the theoretical origins of the IMV model, the key premises underpinning the model, empirical tests of the model and future research directions

The sequencing of stock market liberalization events and corporate financing decisions

We examine if the sequence of stock market liberalization events matters for corporate financing choices. We contrast firms who attain ‘investable’ status through domestic reforms with those who do so by issuing American Depository Receipt programs. We find that the first liberalization event prompts similar corporate responses regardless of the path followed. However, we find differential effects between firms who issue ADRs after realizing financial liberalization and those who use ADR initiations to achieve this status. Here, the sequence matters and the capital structure choices of the two groups are very different.Financing choices; Debt structure; Investability; Cross listing

A Second Relativistic Mean Field and Virial Equation of State for Astrophysical Simulations

We generate a second equation of state (EOS) of nuclear matter for a wide range of temperatures, densities, and proton fractions for use in supernovae, neutron star mergers, and black hole formation simulations. We employ full relativistic mean field (RMF) calculations for matter at intermediate density and high density, and the Virial expansion of a non-ideal gas for matter at low density. For this EOS we use the RMF effective interaction FSUGold, whereas our earlier EOS was based on the RMF effective interaction NL3. The FSUGold interaction has a lower pressure at high densities compared to the NL3 interaction. We calculate the resulting EOS at over 100,000 grid points in the temperature range $T$ = 0 to 80 MeV, the density range $n_B$ = 10$^{-8}$ to 1.6 fm$^{-3}$, and the proton fraction range $Y_p$ = 0 to 0.56. We then interpolate these data points using a suitable scheme to generate a thermodynamically consistent equation of state table on a finer grid. We discuss differences between this EOS, our NL3 based EOS, and previous EOSs by Lattimer-Swesty and H. Shen et al for the thermodynamic properties, composition, and neutron star structure. The original FSUGold interaction produces an EOS, that we call FSU1.7, that has a maximum neutron star mass of 1.7 solar masses. A modification in the high density EOS is introduced to increase the maximum neutron star mass to 2.1 solar masses and results in a slightly different EOS that we call FSU2.1. The EOS tables for FSU1.7 and FSU2.1 are available for download.Comment: updated version according to referee's comments. Phys. Rev. C in pres

The disjointness of stabilizer codes and limitations on fault-tolerant logical gates

Stabilizer codes are a simple and successful class of quantum error-correcting codes. Yet this success comes in spite of some harsh limitations on the ability of these codes to fault-tolerantly compute. Here we introduce a new metric for these codes, the disjointness, which, roughly speaking, is the number of mostly non-overlapping representatives of any given non-trivial logical Pauli operator. We use the disjointness to prove that transversal gates on error-detecting stabilizer codes are necessarily in a finite level of the Clifford hierarchy. We also apply our techniques to topological code families to find similar bounds on the level of the hierarchy attainable by constant depth circuits, regardless of their geometric locality. For instance, we can show that symmetric 2D surface codes cannot have non-local constant depth circuits for non-Clifford gates.Comment: 8+3 pages, 2 figures. Comments welcom

Why Two Renormalization Groups are Better than One

The advantages of using more than one renormalization group (RG) in problems with more than one important length scale are discussed. It is shown that: i) using different RG's can lead to complementary information, i.e. what is very difficult to calculate with an RG based on one flow parameter may be much more accessible using another; ii) using more than one RG requires less physical input in order to describe via RG methods the theory as a function of its parameters; iii) using more than one RG allows one to solve problems with more than one diverging length scale. The above points are illustrated concretely in the context of both particle physics and statistical physics using the techniques of environmentally friendly renormalization. Specifically, finite temperature $\lambda\phi^4$ theory, an Ising-type system in a film geometry, an Ising-type system in a transverse magnetic field, the QCD coupling constant at finite temperature and the crossover between bulk and surface critical behaviour in a semi-infinite geometry are considered.Comment: 17 pages LaTex; to be published in the Proceedings of RG '96, Dubn

Estimating drizzle drop size and precipitation rate using two-colour lidar measurements

A method to estimate the size and liquid water content of drizzle drops using lidar measurements at two wavelengths is described. The method exploits the differential absorption of infrared light by liquid water at 905 nm and 1.5 μm, which leads to a different backscatter cross section for water drops larger than ≈50 μm. The ratio of backscatter measured from drizzle samples below cloud base at these two wavelengths (the colour ratio) provides a measure of the median volume drop diameter D0. This is a strong effect: for D0=200 μm, a colour ratio of ≈6 dB is predicted. Once D0 is known, the measured backscatter at 905 nm can be used to calculate the liquid water content (LWC) and other moments of the drizzle drop distribution. The method is applied to observations of drizzle falling from stratocumulus and stratus clouds. High resolution (32 s, 36 m) profiles of D0, LWC and precipitation rate R are derived. The main sources of error in the technique are the need to assume a value for the dispersion parameter μ in the drop size spectrum (leading to at most a 35% error in R) and the influence of aerosol returns on the retrieval (≈10% error in R for the cases considered here). Radar reflectivities are also computed from the lidar data, and compared to independent measurements from a colocated cloud radar, offering independent validation of the derived drop size distributions

ELISA detection of phenazepam, etizolam, pyrazolam, flubromazepam, diclazepam and delorazepam in blood using Immunalysis® benzodiazepine kit

Phenazepam and etizolam were the first uncontrolled benzodiazepines available for sale in the UK. Pyrazolam, flubromazepam and diclazepam are not used medicinally anywhere in the world; they are produced exclusively for the uncontrolled, recreational market. It is important to know whether potentially abused drugs like these can be detected in routine toxicological screening tests. The purpose of this study was to evaluate whether the Immunalysis® Benzodiazepines ELISA kit could detect phenazepam, etizolam, pyrazolam, flubromazepam, diclazepam and its metabolite delorazepam. Their cross-reactivity was assessed by comparing the absorbance of the drug with that of oxazepam, the reference standard. This study found that these uncontrolled benzodiazepines cross-react sufficiently to produce a positive result with the Immunalysis® Benzodiazepine ELISA kit. Cross-reactivity ranged from 79 to 107% for phenazepam, etizolam, pyrazolam, flubromazepam, diclazepam and delorazepam fortified into blood. The results show that it is possible to detect these newer benzodiazepines with traditional forensic toxicology laboratory tools and it is important to include these benzodiazepines in the confirmation tests