Elastic scattering of intermediate-energy electrons from C_(60) molecules

Experimental and calculated differential cross sections for elastic scattering of electrons by C_(60) molecules at collision energies of 100 to 500 eV are reported. The elastic differential cross sections were measured in a standard crossed-beam apparatus, while the calculations were performed employing the Schwinger multichannel technique at the static-exchange level. Diffraction effects, some due to the overall spherical-cage structure and some to scattering by individual C atoms, are observed in both the measured and calculated cross sections

An investigation of plate-type windborne debris flight using coupled CFD–RBD models. Part I: Model development and validation

AbstractThe development of a coupled computational fluid-dynamics rigid body (CFD–RBD) model is presented. The RBD model deploys rotational quaternions, which are free from the gimbal lock that is associated with Euler rotational matrix. The quaternion model means that the complex 3D spinning flight modes associated with the flight of plate-type windborne debris can be modelled robustly. This paper attempts to determine the accuracy of the CFD–RBD model by comparing the predicted trajectories from a large number of debris simulations with experimentally derived equations of best fit. Agreement is found to be good and, based on the findings, an alternative form for the dimensionless flight distance is presented, which extends the range of the experimental study to longer flight times.The predictions from the CFD–RBD model are then compared against two quasi-steady analytical debris flight models. The second model is based on modified force and moment coefficients, which are informed by the findings from the CFD–RBD model. For plates that have attained a stable, autorotational flight mode, the CFD–RBD and analytical models are in good agreement. Their predictions differ during the initial stages of flight, where the complex non-linear interactions between the plate and its wake are not captured by the analytical models

Targeting Mr Average: Participation, gender equity and school sport partnerships

The School Sport Partnership Programme (SSPP) is one strand of the national strategy for physical education and school sport in England, the physical education and school sport Club Links Strategy (PESSCL). The SSPP aims to make links between school physical education (PE) and out of school sports participation, and has a particular remit to raise the participation levels of several identified under-represented groups, of which girls and young women are one. National evaluations of the SSPP show that it is beginning to have positive impacts on young people's activity levels by increasing the range and provision of extra curricular activities (Office for Standards in Education (OFSTED), 2003, 2004, 2005; Loughborough Partnership, 2005, 2006). This paper contributes to the developing picture of the phased implementation of the programme by providing qualitative insights into the work of one school sport partnership with a particular focus on gender equity. The paper explores the ways in which gender equity issues have been explicitly addressed within the 'official texts' of the SSPP; how these have shifted over time and how teachers are responding to and making sense of these in their daily practice. Using participation observation, interview and questionnaire data, the paper explores how the coordinators are addressing the challenge of increasing the participation of girls and young women. The paper draws on Walby's (2000) conceptualisation of different kinds of feminist praxis to highlight the limitations of the coordinators' work. Two key themes from the data and their implications are addressed: the dominance of competitive sport practices and the PE professionals' views of targeting as a strategy for increasing the participation of under-represented groups. The paper concludes that coordinators work within an equality or difference discourse with little evidence of the transformative praxis needed for the programme to be truly inclusive. © 2008 Taylor & Francis

Improved Searches for HI in Three Dwarf Spheroidal Galaxies

Previous searches for HI in our Galaxy's dwarf spheroidal companions have not been complete enough to settle the question of whether or not these galaxies have HI, especially in their outer parts. We present VLA observations of three dwarf spheroidals: Fornax, Leo II, and Draco, all of which have known stellar velocities. The new data show no HI emission or absorption. Column density limits in emission are 4--7 x 10^18 atoms/cm^2 in the centers of the galaxies. The importance of the new observations is that they cover larger areas than previous searches and they are less plagued by confusion with foreground (Galactic) HI. The apparent absence of neutral gas in the Fornax dwarf spheroidal is especially puzzling because recent photometry shows evidence of stars only 10^8 years old. We discuss whether the VLA observations could have missed significant amounts of HI.Comment: 20 pages, 7 figures; to appear in the Astronomical Journa

First Clear Signature of an Extended Dark Matter Halo in the Draco Dwarf Spheroidal

We present the first clear evidence for an extended dark matter halo in the Draco dwarf spheroidal galaxy based on a sample of new radial velocities for 159 giant stars out to large projected radii. Using a two parameter family of halo models spanning a range of density profiles and velocity anisotropies, we are able to rule out (at about the 2.5 sigma confidence level) haloes in which mass follows light. The data strongly favor models in which the dark matter is significantly more extended than the visible dwarf. However, haloes with harmonic cores larger than the light distribution are also excluded. When combined with existing measurements of the proper motion of Draco, our data strongly suggest that Draco has not been tidally truncated within ~1 kpc. We also show that the rising velocity dispersion at large radii represents a serious problem for modified gravity (MOND).Comment: to be published in ApJL; 5 pages, 4 figure

Casimir force under the influence of real conditions

The Casimir force is calculated analytically for configurations of two parallel plates and a spherical lens (sphere) above a plate with account of nonzero temperature, finite conductivity of the boundary metal and surface roughness. The permittivity of the metal is described by the plasma model. It is proved that in case of the plasma model the scattering formalism of quantum field theory in Matsubara formulation underlying Lifshitz formula is well defined and no modifications are needed concerning the zero-frequency contribution. The temperature correction to the Casimir force is found completely with respect to temperature and perturbatively (up to the second order in the relative penetration depth of electromagnetic zero-point oscillations into the metal) with respect to finite conductivity. The asymptotics of low and high temperatures are presented and contributions of longitudinal and perpendicular modes are determined separately. Serving as an example, aluminium test bodies are considered showing good agreement between the obtained analytical results and previously performed numerical computations. The roughness correction is formally included and formulas are given permitting to calculate the Casimir force under the influence of all relevant factors

Screening for latent TB, HIV, and hepatitis B/C in new migrants in a high prevalence area of London, UK: a cross-sectional study.

BACKGROUND: Rising rates of infectious diseases in international migrants has reignited the debate around screening. There have been calls to strengthen primary-care-based programmes, focusing on latent TB. We did a cross-sectional study of new migrants to test an innovative one-stop blood test approach to detect multiple infections at one appointment (HIV, latent tuberculosis, and hepatitis B/C) on registration with a General Practitioner (GP) in primary care. METHODS: The study was done across two GP practices attached to hospital Accident and Emergency Departments (A&E) in a high migrant area of London for 6 months. Inclusion criteria were foreign-born individuals from a high TB prevalence country (>40 cases per 100,000) who have lived in the UK ≤ 10 years, and were over 18 years of age. All new migrants who attended a New Patient Health Check were screened for eligibility and offered the blood test. We followed routine care pathways for follow-up. RESULTS: There were 1235 new registrations in 6 months. 453 attended their New Patient Health Check, of which 47 (10.4%) were identified as new migrants (age 32.11 years [range 18-72]; 22 different nationalities; time in UK 2.28 years [0-10]). 36 (76.6%) participated in the study. The intervention only increased the prevalence of diagnosed latent TB (18.18% [95% CI 6.98-35.46]; 181.8 cases per 1000). Ultimately 0 (0%) of 6 patients with latent TB went on to complete treatment (3 did not attend referral). No cases of HIV or hepatitis B/C were found. Foreign-born patients were under-represented at these practices in relation to 2011 Census data (Chi-square test -0.111 [95% CI -0.125 to -0.097]; p < 0.001). CONCLUSION: The one-stop approach was feasible in this context and acceptability was high. However, the number of presenting migrants was surprisingly low, reflecting the barriers to care that this group face on arrival, and none ultimately received treatment. The ongoing UK debate around immigration checks and charging in primary care for new migrants can only have negative implications for the promotion of screening in this group. Until GP registration is more actively promoted in new migrants, a better place to test this one-stop approach could be in A&E departments where migrants may present in larger numbers

Tackling mental health: the role of professional football clubs

In the UK, professional football clubs are being used as settings for the delivery of interventions that promote mental health in a number of ways including (i) the delivery of physical activity interventions to improve the mental health of the general population, (ii) the delivery of physical activity interventions for people experiencing mental illness, and (iii) the delivery of community mental health services within the confines of the football club. This research note offers insights into mental health interventions delivered within, and by, professional football clubs and the available evidence concerning their reach, effectiveness and impact. The findings suggest that professional football clubs can help to facilitate access to mental health services, particularly among young people, for whom accessing such services may be highly stigmatized. Furthermore, the findings highlight that such interventions have a positive impact on health. However, in order to capitalize on this opportunity funding agencies and commissioners must provide appropriate resources (human and financial) for effective delivery and evaluation. Furthermore, a more strategic approach to working towards the mental health agenda must be adopted. It is argued that this change in practice would allow professional football clubs to offer those in need access to high-quality interventions

Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal

We present a large area photometric survey of the Ursa Minor dSph. We identify UMi giant star candidates extending to ~3 deg from the center of the dSph. Comparison to previous catalogues of stars within the tidal radius of UMi suggests that our photometric luminosity classification is 100% accurate. Over a large fraction of the survey area, blue horizontal branch stars associated with UMi can also be identified. The spatial distribution of both the UMi giant stars and the BHB stars are remarkably similar, and a large fraction of both samples of stars are found outside the tidal radius of UMi. An isodensity contour map of the stars within the tidal radius of UMi reveals two morphological peculiarities: (1) The highest density of dSph stars is offset from the center of symmetry of the outer isodensity contours. (2) The overall shape of the outer contours appear S-shaped. We find that previously determined King profiles with ~50' tidal radii do not fit well the distribution of our UMi stars. A King profile with a larger tidal radius produces a reasonable fit, however a power law with index -3 provides a better fit for radii > 20'. The existence of UMi stars at large distances from the core of the galaxy, the peculiar morphology of the dSph within its tidal radius, and the shape of its surface density profile all suggest that UMi is evolving significantly due to the tidal influence of the Milky Way. However, the photometric data on UMi stars alone does not allow us to determine if the candidate extratidal stars are now unbound or if they remain bound to the dSph within an extended dark matter halo. (Abridged)Comment: accepted by AJ, 32 pages, 15 figures, emulateapj5 styl