5,721 research outputs found

    Brexit and the Future of English Law

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    Sir David Lloyd Jones was the 2017 Victoria University Law Dean's Fellow. The following is a revised version of the lecture given at Victoria University of Wellington on 23 August 2017 on the likely impact of Brexit on English law. It is based on the information available at that date

    The influence of binarity on the morpho-kinematics of planetary nebulae

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    The role of central star binarity in the shaping of planetary nebulae (PNe) has been the subject of much debate, with single stars believed to be incapable of producing the most highly collimated morphologies. However, observational support for binary-induced shaping has been sadly lacking. Here, we highlight the results of a continuing programme to spatio-kinematically model the morphologies of all PNe known to contain a close binary central star. Spatio-kinematical modelling is imperative for these objects, as it circumvents the degeneracy between morphology and orientation which can adversely affect determinations of morphology based on imaging alone. Furthermore, spatio-kinematical modelling accurately determines the orientation of the nebular shell, allowing the theoretically predicted perpendicular alignment, between nebular symmetry axis and binary orbital plane, to be tested. To date, every PN subjected to this investigation has displayed the predicted alignment, indicating that binarity has played an important role in the formation and evolution of these nebulae. The further results from this programme will be key, not only in determining whether binary interaction is responsible for shaping the studied PNe, but also in assessing the importance of binarity in the formation and evolution of all PNe in general.Comment: 2 pages, 2 tables, proceedings of the IAU Symposium No. 283, Planetary Nebulae: An Eye to the Futur

    Every student counts: promoting numeracy and enhancing employability

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    This three-year project investigated factors that influence the development of undergraduates’ numeracy skills, with a view to identifying ways to improve them and thereby enhance student employability. Its aims and objectives were to ascertain: the generic numeracy skills in which employers expect their graduate recruits to be competent and the extent to which employers are using numeracy tests as part of graduate recruitment processes; the numeracy skills developed within a diversity of academic disciplines; the prevalence of factors that influence undergraduates’ development of their numeracy skills; how the development of numeracy skills might be better supported within undergraduate curricula; and the extra-curricular support necessary to enhance undergraduates’ numeracy skills

    Wattle function and territoriality in the South Island saddleback (Philesturnus carunculatus)1

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    The South Island saddleback (Philesturnus carunculatus) is an endangered bird endemic to New Zealand. Both males and females possess wattles, which are colourful fleshy structures that hang from the lower beak. Although a wide range of birds have wattles, the selection pressures and behavioural function of these biological ornaments remain poorly understood. In this study, behavioural observations, morphological measures, and a playback experiment were used to investigate how wattles are used by South Island saddlebacks in their natural habitat. Wattles were found to be monomorphic when body mass was accounted for, and they were observed to engorge in both aggressive and non-aggressive visual displays. In the playback experiment, wattle engorgement in saddlebacks was significantly associated with territorial intrusions in males but not in females, although females were significantly more likely to engorge their wattles and display in the absence of their mate. Larger males with bigger wattles did not have significantly stronger territorial responses. These results provide the first experimental evidence for the functional role that wattle engorgement plays in saddleback signalling behaviour. The markedly similar visual display behaviour between sexes, which is used in both aggressive and non-aggressive contexts, provides insight into possible selection pressures acting in the evolutionary maintenance of wattles

    Quantum Process Tomography of the Quantum Fourier Transform

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    The results of quantum process tomography on a three-qubit nuclear magnetic resonance quantum information processor are presented, and shown to be consistent with a detailed model of the system-plus-apparatus used for the experiments. The quantum operation studied was the quantum Fourier transform, which is important in several quantum algorithms and poses a rigorous test for the precision of our recently-developed strongly modulating control fields. The results were analyzed in an attempt to decompose the implementation errors into coherent (overall systematic), incoherent (microscopically deterministic), and decoherent (microscopically random) components. This analysis yielded a superoperator consisting of a unitary part that was strongly correlated with the theoretically expected unitary superoperator of the quantum Fourier transform, an overall attenuation consistent with decoherence, and a residual portion that was not completely positive - although complete positivity is required for any quantum operation. By comparison with the results of computer simulations, the lack of complete positivity was shown to be largely a consequence of the incoherent errors during the quantum process tomography procedure. These simulations further showed that coherent, incoherent, and decoherent errors can often be identified by their distinctive effects on the spectrum of the overall superoperator. The gate fidelity of the experimentally determined superoperator was 0.64, while the correlation coefficient between experimentally determined superoperator and the simulated superoperator was 0.79; most of the discrepancies with the simulations could be explained by the cummulative effect of small errors in the single qubit gates.Comment: 26 pages, 17 figures, four tables; in press, Journal of Chemical Physic

    A Systematic Examination of the 2013 ACC/AHA Pooled Cohort Risk Assessment Tool for Atherosclerotic Cardiovascular Disease

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    AbstractBackgroundThe 2013 American College of Cardiology/American Heart Association updated cholesterol guidelines recommend the use of Pooled Cohort Equations to estimate 10-year absolute risk for atherosclerotic cardiovascular disease (ASCVD) in primary prevention.ObjectivesThis study sought to systematically examine the Pooled Cohort Equations to determine risk factor levels required to exceed risk thresholds outlined in new cholesterol guidelines.MethodsWe entered continuous risk factor levels in isolation and in specified combinations with the risk tool, and we observed predicted risk output patterns. We used the 10-year ASCVD risk threshold of ≄7.5% as a clinically relevant risk threshold.ResultsWe demonstrated that a hypothetical man or woman can reach clinically relevant risk thresholds throughout the eligible age spectrum of 40 to 79 years of age, depending on the associated risk factor burden in all race-sex groups. Age continues to be a major determinant of 10-year ASCVD risk for both men and women. Compared with the previous risk assessment tool used in cholesterol guidelines, the inclusion of a stroke endpoint and use of race-specific coefficients permit identification of at-risk African Americans and non-Hispanic white women at much younger ages and lower risk factor levels.ConclusionsThese data provide context of specific risk factor levels and groups of individuals who are likely to have 10-year ASCVD risk estimates ≄7.5%. Age continues to be a major driver of risk, which highlights the importance of the clinician-patient discussion before statin therapy is initiated

    The influence of central star binarity on the morphologies of planetary nebulae

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    Central star binarity is often invoked as the main driver behind the shaping of aspherical planetary nebulae, however observational support for this hypothesis is lacking. This work presented in this thesis attempts to observationally test this theory by investigating the relationship between central star binarity and nebular morphology for several planetary nebulae. The discovery of six new binary central star systems is also reported. A detailed spatio-kinematical analysis of Abell 41 was performed, showing the nebula to have a bipolar morphology waisted by a toroidal structure, the symmetry axis of which is found to be perpendicular to the plane of the central binary. This alignment is exactly as predicted, indicating that the central binary, MT Ser, has played a significant role in shaping Abell 41. This is only the second planetary nebulae to have had this link, between binary and nebular inclination, explicitly shown. A spatio-kinematic model has been developed for ETHOS 1, indicating that its spectacular polar outflows are kinematically older than the central region of the nebula. This finding is discussed in the context of binary evolution, and it is concluded that the polar outflows in these nebulae are probably formed before their central binaries have entered the common-envelope phase. The central star of ETHOS 1 has yet to be the subject of detailed study, and as such, the orientation of the nebula could not be compared to that of its central binary. A spatio-kinematical analysis of SuWt 2 is presented, proving that the nebular ring is in fact at the waist of a much larger, extended bipolar structure. SuWt 2 is not known to contain a post-main sequence central star, required to eject and ionise the nebular shell, but rather a double A-type binary. The results of the analysis are discussed with relation to possible formation scenarios for SuWt 2. It is concluded that, while neither component of the double A-type binary could be the nebular progenitor, the presence of a third component to the system, which would have been the progenitor, cannot be ruled out. However, as there is no evidence that the central star of SuWt 2 is a binary alone, it is suggested that SuWt 2 should be removed from future lists of planetary nebulae known to host a binary central star. A sample of sixteen central stars of planetary nebulae, displaying morphological traits believed to be typical of central star binarity, were monitored for signs of periodic photometric variability associated with binarity. Six new photometrically variable close-binary stars were discovered, representing a ~15% increase on the previously known figure. The binary detection success rate from this investigation is compared to that of other surveys, and it is concluded that, while the results are promising, a more rigorous test is required to fully assess the extent to which specific morphological traits can be used as indicators of central star binarity.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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