10,722 research outputs found

    Sigma-model soliton intersections from exceptional calibrations

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    A first-order `BPS' equation is obtained for 1/8 supersymmetric intersections of soliton-membranes (lumps) of supersymmetric (4+1)-dimensional massless sigma models, and a special non-singular solution is found that preserves 1/4 supersymmetry. For 4-dimensional hyper-K\"ahler target spaces (HK4HK_4) the BPS equation is shown to be the low-energy limit of the equation for a Cayley-calibrated 4-surface in \bE^4\times HK_4. Similar first-order equations are found for stationary intersections of Q-lump-membranes of the massive sigma model, but now generic solutions preserve either 1/8 supersymmetry or no supersymmetry, depending on the time orientation.Comment: 21 pages. Version 3: Minor corrections and one further reference: version published in JHE

    Staying true with the help of others: doxastic self-control through interpersonal commitment

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    I explore the possibility and rationality of interpersonal mechanisms of doxastic self-control, that is, ways in which individuals can make use of other people in order to get themselves to stick to their beliefs. I look, in particular, at two ways in which people can make interpersonal epistemic commitments, and thereby willingly undertake accountability to others, in order to get themselves to maintain their beliefs in the face of anticipated “epistemic temptations”. The first way is through the avowal of belief, and the second is through the establishment of collective belief. I argue that both of these forms of interpersonal epistemic commitment can function as effective tools for doxastic self-control, and, moreover, that the control they facilitate should not be dismissed as irrational from an epistemic perspective

    The (20)Ne interaction in extended matter

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    Although heavy ion transport theory is developed to a relatively advanced stage, the present limitation in biomedical and electronic applications is the uncertainty in nuclear fragmentation parameters. The present status on Ne-20 beams is discussed and useful formulae are presented for future use in analysis of beam transport experiments

    Fragmentation in Carbon Therapy Beams

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    The state of the art Monte Carlo code HETC-HEDS was used to simulate spallation products, secondary neutron, and secondary proton production in A-150 Tissue Equivalent Plastic phantoms to investigate fragmentation of carbon therapy beams. For a 356 MeV/Nucleon carbon ion beam, production of charged particles heavier than protons was 0.24 spallation products per incident carbon ion with atomic numbers ranging from 1 through 5 (hydrogen to boron). In addition, there were 4.73 neutrons and 2.95 protons produced per incident carbon ion. Furthermore, as the incident energy increases, the neutron production rate increases at a rate of 20% per 10 MeV/nucleon. Secondary protons were created at a rate between 2.62-2.87 per carbon ion, while spallation products were created at a rate between 0.20-0.24 per carbon ion

    After Regions: what next for local enterprise partnerships?

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    Standing out as an oddity in comparison to the convergence of policy across EU nations whereby the merits of regional apparatus – however defined – for administering development support appear to be accepted, the UK Government has abandoned England’s experiment with regionalism. Under the banner of localism, providing the thinnest of masks for swingeing public expenditure cuts, sub-national development activity (encompassing planning, regeneration, infrastructure development, enterprise support and spatial leadership) is in the throes of considerable economic shifts, policy flux and institutional upheaval (Ward & Hardy, 2012). This article attempts to address some of the questions posed in The regional lacuna: a preliminary map of the transition from Regional Development Agencies to Local Economic Partnerships (Pugalis, 2011) and helps to advance some of the points relating to the emerging sub-national development landscape published in recent issues of Regions (e.g. Bailey, 2011). The purpose is to take stock of policy developments underway by means of a post-regional sub-national review in order to outline the future development trajectory of Local Enterprise Partnerships

    Radial velocity variations of the pulsating subdwarf B star PG 1605+072

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    We present an analysis of high-speed spectroscopy of the pulsating subdwarf B star PG 1605+072. Periodic radial motions are detected at frequencies similar to those reported for photometric variations in the star, with amplitudes of up to 6 km/s. Differences between relative strengths for given frequency peaks for our velocity data and previously measured photometry are probably a result of shifting of power between modes over time. Small differences in the detected frequencies may also indicate mode-shifting. We report the detection of line-shape variations using the moments of the cross correlation function profiles. It may be possible to use the moments to identify the star's pulsation modes.Comment: 5 pages, 6 figure

    Spin period change and the magnetic fields of neutron stars in Be X-ray binaries in the Small Magellanic Cloud

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    We report on the long-term average spin period, rate of change of spin period and X-ray luminosity during outbursts for 42 Be X-ray binary systems in the Small Magellanic Cloud. We also collect and calculate parameters of each system and use these data to determine that all systems contain a neutron star which is accreting via a disc, rather than a wind, and that if these neutron stars are near spin equilibrium, then over half of them, including all with spin periods over about 100 s, have magnetic fields over the quantum critical level of 4.4x10^13 G. If these neutron stars are not close to spin equilibrium, then their magnetic fields are inferred to be much lower, of the order of 10^6-10^10 G, comparable to the fields of neutron stars in low-mass X-ray binaries. Both results are unexpected and have implications for the rate of magnetic field decay and the isolated neutron star population.Comment: 22 pages, 50 figures; to appear in MNRA

    Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355

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    We report the detection of a strong, organized magnetic field in the helium-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Canada-France-Hawaii Telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. HR 7355 is both the most rapidly rotating known main-sequence magnetic star and the most rapidly rotating helium-strong star, with vsin⁥iv \sin i = 300 ±\pm 15 km s−1^{-1} and a rotational period of 0.5214404 ±\pm 0.0000006 days. We have modeled our eight longitudinal magnetic field measurements assuming an oblique dipole magnetic field. Constraining the inclination of the rotation axis to be between 38∘38^{\circ} and 86∘86^{\circ}, we find the magnetic obliquity angle to be between 30∘30^{\circ} and 85∘85^{\circ}, and the polar strength of the magnetic field at the stellar surface to be between 13-17 kG. The photometric light curve constructed from HIPPARCOS archival data and new CTIO measurements shows two minima separated by 0.5 in rotational phase and occurring 0.25 cycles before/after the magnetic extrema. This photometric behavior coupled with previously-reported variable emission of the Hα\alpha line (which we confirm) strongly supports the proposal that HR 7355 harbors a structured magnetosphere similar to that in the prototypical helium-strong star, σ\sigma Ori E.Comment: 6 pages, 3 figures. Accepted for publication in MNRAS Letter

    Development and implementation of the Bachelor of Nursing (Conversion) course in Vanuatu.

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    CONTEXT: Vanuatu, a Pacific Island nation in the Western Pacific region, has to date educated its nurses by diploma program. Research evidence in developed countries has consistently shown that nurses educated by bachelor degree improve patient health outcomes and reduce hospital length of stay. In seeking to improve health outcomes, the Vanuatu Ministry of Health decided to introduce a new Bachelor of Nursing degree to provide a skilled, safe nursing workforce for the provision of health care to its peoples{1-3}. The curriculum for this degree was to be developed by Ni-Vanuatu nurse educators with the collaboration of educators from the WHO Collaborating Centre, University of Technology Sydney. However, it was first necessary to upgrade (from diploma to bachelor level) the qualifications of teachers and senior nursing practitioners who would lead the new degree course by introducing a Bachelor of Nursing (Conversion) course. ISSUES: In order to design and implement a Bachelor of Nursing (Conversion) course that would be relevant for the educational and healthcare context in Vanuatu and that would meet qualification requirements of the local regulatory bodies, it was essential to build collaborative relationships with key stakeholders in Vanuatu. A second key concern was to design a program that would cater for participants who were working full time, who were not all living in the same physical location, and who had limited access to internet technology and resources. The course also needed to take into account that participants were multilingual, and that English was not their first language. LESSONS LEARNED: Lessons learned included the importance of coming to understand the sociocultural nexus within which this course was developed and implemented, as well as appreciating the constraints that affect nursing education within the Pacific
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