Nuclear alpha-clustering, superdeformation, and molecular resonances

Nuclear alpha-clustering has been the subject of intense study since the advent of heavy-ion accelerators. Looking back for more than 40 years we are able today to see the connection between quasimolecular resonances in heavy-ion collisions and extremely deformed states in light nuclei. For example superdeformed bands have been recently discovered in light N=Z nuclei such as $^{36}$Ar, $^{40}$Ca, $^{48}$Cr, and $^{56}$Ni by $\gamma$-ray spectroscopy. The search for strongly deformed shapes in N=Z nuclei is also the domain of charged-particle spectroscopy, and our experimental group at IReS Strasbourg has studied a number of these nuclei with the charged particle multidetector array {\sc Icare} at the {\sc Vivitron} Tandem facility in a systematical manner. Recently the search for $\gamma$-decays in $^{24}$Mg has been undertaken in a range of excitation energies where previously nuclear molecular resonances were found in $^{12}$C+$^{12}$C collisions. The breakup reaction $^{24}$Mg$+^{12}$C has been investigated at E$_{lab}$($^{24}$Mg) = 130 MeV, an energy which corresponds to the appropriate excitation energy in $^{24}$Mg for which the $^{12}$C+$^{12}$C resonance could be related to the breakup resonance. Very exclusive data were collected with the Binary Reaction Spectrometer in coincidence with {\sc Euroball IV} installed at the {\sc Vivitron}.Comment: 10 pages, 4 eps figures included. Invited Talk 10th Nuclear Physics Workshop Marie and Pierre Curie, Kazimierz Dolny Poland, Sep. 24-28, 2003; To be published in International Journal of Modern Physics

Hypervelocity Stars from the Andromeda Galaxy

Hypervelocity stars (HVSs) discovered in the Milky Way (MW) halo are thought to be ejected from near the massive black hole (MBH) at the galactic centre. In this paper we investigate the spatial and velocity distributions of the HVSs which are expected to be similarly produced in the Andromeda galaxy (M31). We consider three different HVS production mechanisms: (i) the disruption of stellar binaries by the galactocentric MBH; (ii) the ejection of stars by an in-spiraling intermediate mass black hole; and (iii) the scattering of stars off a cluster of stellar-mass black holes orbiting around the MBH. While the first two mechanisms would produce large numbers of HVSs in M31, we show that the third mechanism would not be effective in M31. We numerically calculate 1.2*10^6 trajectories of HVSs from M31 within a simple model of the Local Group and hence infer the current distribution of these stars. Gravitational focusing of the HVSs by the MW and the diffuse Local Group medium leads to high densities of low mass (~ solar mass) M31 HVSs near the MW. Within the virialized MW halo, we expect there to be of order 1000 HVSs for the first mechanism and a few hundred HVSs for the second mechanism; many of these stars should have distinctively large approach velocities (< -500 km/s). In addition, we predict ~5 hypervelocity RGB stars within the M31 halo which could be identified observationally. Future MW astrometric surveys or searches for distant giants could thus find HVSs from M31.Comment: 14 pages, 6 figures, changed to match version accepted by MNRA

Shot-noise-limited spin measurements in a pulsed molecular beam

Heavy diatomic molecules have been identified as good candidates for use in electron electric dipole moment (eEDM) searches. Suitable molecular species can be produced in pulsed beams, but with a total flux and/or temporal evolution that varies significantly from pulse to pulse. These variations can degrade the experimental sensitivity to changes in spin precession phase of an electri- cally polarized state, which is the observable of interest for an eEDM measurement. We present two methods for measurement of the phase that provide immunity to beam temporal variations, and make it possible to reach shot-noise-limited sensitivity. Each method employs rapid projection of the spin state onto both components of an orthonormal basis. We demonstrate both methods using the eEDM-sensitive H state of thorium monoxide (ThO), and use one of them to measure the magnetic moment of this state with increased accuracy relative to previous determinations.Comment: 12 pages, 6 figure

Visual Field Progression in Glaucoma What Is the Specificity of the Guided Progression Analysis?

Purpose: To estimate the specificity of the Guided Progression Analysis (GPA) (Carl Zeiss Meditec, Dublin, CA) in individual patients with glaucoma. Design: Observational cohort study. Participants: Thirty patients with open-angle glaucoma. Methods: In 30 patients with open-angle glaucoma, 1 eye (median mean deviation [MD], −2.5 decibels [dB]; interquartile range, −4.4 to −1.3 dB) was tested 12 times over 3 months (Humphrey Field Analyzer, Carl Zeiss Meditec; SITA Standard, 24-2). “Possible progression” and “likely progression” were determined with the GPA. These analyses were repeated after the order of the tests had been randomly rearranged (1000 unique permutations). Main Outcome Measures: Rate of false-positive alerts of “possible progression” and “likely progression” with the GPA. Results: On average, the specificity of the GPA “likely progression” alert was high—for the entire sample, the mean rate of false-positive alerts after 10 follow-up tests was 2.6%. With “possible progression,” the specificity was considerably lower (false-positive rate, 18.5%). Most important, the cumulative rate of false-positive alerts varied substantially among patients, from 0.31, P≤0.10). Conclusions: On average, progression criteria currently used in the GPA have high specificity, but some patients are more likely to show false-positive alerts than others. This is a natural consequence of population-based change criteria and may not matter in clinical trials and studies in which large groups of patients are compared. However, it must be considered when the GPA is used in clinical practice where specificity needs to be controlled for individual patients

Management actions to address the climate emergency: Motivations and barriers for SMEs and other societal micro/meso-level groups

Initiatives to tackle the climate emergency have tended to focus on large-scale actions that governments and investors (societal macro-levels) can take and smaller-scale individual habits, with limited attention given to the groups that form society between those ends of the spectrum (societal micro/meso-levels). This research aims to traverse that gap by studying three societal micro/meso-level groups; from the private, public and voluntary sectors, as represented by business, community and campaign groups. Existing literature and focus groups are used to identify what motivates actions on climate change, while exposing barriers that may drive choices of inaction. The study shows that concerns for the future and personal ethics play vital roles across business, community and campaign groups, while the principal barriers include difficulties in accessing support schemes and changes in political priorities. Better networking and knowledge exchange are considered essential for meaningful progress. This provides a new framework for management education to support organisations in tackling climate-related issues. Action guides may be developed and task-forces trained to provide hands-on support, especially for SMEs and local communities. The enthusiasm of younger people and campaigners, combined with others’ experiences, would create a powerful platform for climate emergency actions

A randomised controlled trial of ion-exchange water softeners for the treatment of eczema in children

Epidemiological studies and anecdotal reports suggest a possible link between household use of hard water and atopic eczema. We sought to test whether installation of an ion-exchange water softener in the home can improve eczema in children

Massive open star clusters using the VVV survey III: A young massive cluster at the far edge of the Galactic bar

Context: Young massive clusters are key to map the Milky Way's structure, and near-IR large area sky surveys have contributed strongly to the discovery of new obscured massive stellar clusters. Aims: We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVV CL086, using part of its OB-stellar population. Methods: We physically characterized the cluster using $JHK_S$ near-infrared photometry from ESO public survey VVV images, using the VVV-SkZ pipeline, and near-infrared $K$-band spectroscopy, following the methodology presented in the first article of the series. Results: Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster members from the statistically field-star decontaminated CMD, have spectral types between O9 and B0V. According to our analysis, this young cluster ($1.0$ Myr $<$ age $< 5.0$ Myr) is located at a distance of $11^{+5}_{-6}$ kpc, and we estimate a lower limit for the cluster total mass of $(2.8^{+1.6}_{-1.4})\cdot10^3 {M}_{\odot}$. It is likely that the cluster contains even earlier and more massive stars.Comment: Accepted for publication as a Letter in A&