5,252 research outputs found
Anomalous isotopic predissociation in the F³Πu(v=1) state of O₂
Using a tunable, narrow-bandwidth vacuum-ultraviolet source based on third-harmonic generation from excimer-pumped dye-laser radiation, the F³Πu←X³Σg-(1,0)photoabsorption cross sections of ¹⁶O₂ and ¹⁸O₂ have been recorded in high resolution. Rotational analyses have been performed and the resultant F(v=1) term values fitted to the ³Π Hamiltonian of Brown and Merer [J. Mol. Spectrosc. 74, 488 (1979)]. A large rotationless isotope effect is observed in the F(v=1)predissociation, wherein the Lorentzian linewidth component for ¹⁸O₂ is a factor of ∼50 smaller than the corresponding ¹⁶O₂linewidth. This effect, a consequence of the nonadiabatic rotationless predissociation mechanism, is described using a coupled-channel treatment of the strongly Rydberg-valence-mixed 3Πu states. Significant J, e/f-parity, and sublevel dependencies observed in the isotopic F(v=1) rotational widths are found to derive from an indirect predissociation mechanism involving an accidental degeneracy with the E³Σ−u(v=3) level, itself strongly predissociated by ³Σ−u Rydberg-valence interactions, together with L-uncoupling (rotational) interactions between the Rydberg components of the F and E states. Transitions into the E(v=3) level are observed directly for the first time, specifically in the ¹⁸O₂ spectrumPartial support
was provided by an NSF International Opportunities for Scientists
and Engineers Program Grant No. INT-9513350, and
Visiting Fellowships for G.S. and J.B.W. at the Australian
National University
Challenges associated with x-ray imaging of stretcher-bound patients
Patients often arrive at imaging departments on stretchers, and in certain circumstances they must remain on the stretcher for the imaging examination to reduce the likelihood of exacerbating injuries. Imaging stretcher-bound patients can be challenging, with many physical and technical variables to consider. These challenges occur because of differences between imaging a patient on a tabletop and imaging a patient on a stretcher. This article reviews the issues associated with imaging stretcher-
bound patients, including the unavailability of the automatic exposure control, different grids used, geometric factors, and variability in stretcher design
Reviewing research evidence and the case of participation in sport and physical recreation by black and minority ethnic communities
The paper addresses the implications of using the process of systematic review in the many areas of leisure where there is a dearth of material that would be admitted into conventional Cochrane Reviews. This raises important questions about what constitutes legitimate knowledge, questions that are of critical import not just to leisure scholars, but to the formulation of policy. The search for certainty in an area that lacks conceptual consensus results in an epistemological imperialism that takes a geocentric form. While clearly, there is a need for good research design whatever the style of research, we contend that the wholesale rejection of insightful research is profligate and foolhardy. A mechanism has to be found to capitalise on good quality research of whatever form. In that search, we draw upon our experience of conducting a review of the material available on participation in sport and physical recreation by people from Black and minority ethnic groups. The paper concludes with a proposal for a more productive review process that makes better use of the full panoply of good quality research available. © 2012 © 2012 Taylor & Francis
Expression of Sox1, Sox2 and Sox9 is maintained in adult human cerebellar cortex
Neural stem cells (NSCs) have been found to reside in defined areas of the vertebrate brain, where they can be identified by the expression of specific markers such as Sox1, Sox2 and Sox9. In the mouse, expression of Sox1, Sox2 and Sox9 genes has recently been reported outside of these recognised NSC niches, in the Purkinje cell layer of the adult cerebellum. The present study establishes that expression of these marker genes is also found in the human cerebellum beyond the maturation phase. Expression of Sox1, Sox2 and Sox9 was detected at the mRNA level in both foetal and adult cerebellum samples, suggesting that the maintenance of these markers in adult tissue is also observed in the human cerebellum. Expression of these markers was further confirmed at the protein level on human tissue sections, as Sox1, Sox2 and Sox9 expression was detected in the Purkinje cell layer of the adult cerebellum. The present study demonstrates that Sox1 and Sox2 are expressed in the human adult cerebellum, outside of the characterised NSC niches. © 2008 Elsevier Ireland Ltd. All rights reserved
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On the lifetime and one-year views of reserve risk, with application to IFRS 17 and Solvency II risk margins
This paper brings together analytic and simulation-based approaches to reserve risk in general (P&C) insurance, applied to the traditional actuarial view of risk over the lifetime of the liabilities and to the one-year view of Solvency II. It also connects the lifetime and one-year views of risk. The framework of the model in Mack (1993) is used throughout, although the results have wider applicability.
The advantages of a simulation-based approach are highlighted, giving a full predictive distribution, which is used to estimate risk margins under Solvency II and risk adjustments under IFRS 17. We discuss methods for obtaining capital requirements in a cost-of-capital risk margin, and methods for estimating risk adjustments using risk measures applied to a simulated distribution of the outstanding liabilities over their lifetime
Penalty finite element approximations of the stationary power- law Stokes problem
Finite element approximations of the stationary power-law Stokes problem using penalty
formulation are considered. A priori error estimates under appropriate smoothness assumptions on the
solutions are established without assuming a discrete version of the BB condition. Numerical solutions
are presented by implementing a nonlinear conjugate gradient metho
Patient safety in undergraduate radiography curricula : a European perspective
Purpose: To establish an understanding of patient safety within radiography education across Europe by surveying higher education institutions registered as affiliate members of the European Federation of Radiographer Societies (EFRS).
Method: An online survey was developed to ascertain data on: programme type, patient safety definitions, relevant safety topics, specific areas taught, teaching and assessment methods, levels of teaching and curriculum drivers. Responses were identifiable in terms of educational institution and country. All 54 affiliated educational institutions were invited to participate. Descriptive and thematic analyses are reported.
Results: A response rate of 61.1% (n = 33) was achieved from educational institutions representing 19 countries. Patient safety topics appear to be extremely well covered across curricula, however, topics including radiation protection and optimisation were not reported as being taught at an ‘advanced level’ by five and twelve respondents, respectively. Respondents identified the clinical department as the location of most patient safety-related teaching.
Conclusions: Patient safety topics are deeply embedded within radiography curricula across Europe. Variations exist in terms of individual safety topics included, teaching and assessment methods, and the depth in which subjects are taught. Results from this study provide a baseline for assessing developments in curricula and can also serve as a benchmark for comparisons
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