129 research outputs found

    Commentary on Aikin

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    Threshold values for the protection of marine ecosystems from NORM in subsea oil and gas infrastructure

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    Acknowledgements The authors thank Professor Claus Otto (Curtin University) and Professor Richard Neilson (National Decommissioning Centre, Aberdeen, UK.) for comments and support to the project team; and, Sam Jarvis (National Environment Resources Australia), Professor Peter Macreadie, Dr Rick Tinker, and the industry partners of the National Decommissioning Research Initiative for helpful comments to this project. Funding This research was funded by the Australian Government’s Industry Growth Centre National Energy Resources Australia (NERA) through a National Decommissioning Research Initiative (NDRI) grant to Curtin University. The NDRI project was funded by eight industry partners including Shell Australia, Esso Australia, Chevron Australia, BHP Petroleum, Woodside Energy, Santos Limited, ConocoPhillips Pipeline Australia, and Vermilion Oil and Gas Australia. AH is partly funded by the National Decommissioning Centre, Scotland, and the University of Aberdeen.Peer reviewedPublisher PD

    The English National Chlamydia Screening Programme: variations in positivity in 2007/2008.

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    BACKGROUND: The purpose of this study was to examine variation in positivity within the English National Chlamydia Screening Programme during 2007/2008. METHODS: Data were analyzed using multivariable logistic regression. The outcome measure was positivity. Funnel plots were used to explore variation in positivity according to screening volume. RESULTS: Three hundred and thirty-four thousand nine hundred and two screening tests were done, 29% of which were in men. Overall positivity was 7.6% in men and 9.3% in women. For men, positivity increased rapidly to plateau from ages 19 to 24. For women, rates peaked at 18 years-those aged 21 being at the same risk of chlamydial infection as 16-year-olds. For men and women, positivity was generally higher for those of black or mixed ethnicity compared with whites, whereas Asians were at lower risk. Similarly, risk of infection for men and women varied by screening venue. Multivariable analysis showed that, for men and women positivity varied significantly with age, ethnicity, screening venue attended, whether the young people had had a new sexual partner in the past 3 months, and whether the patient had had 2 or more sexual partners in the past year. Positivity did not vary significantly with implementation phase. CONCLUSIONS: This is the largest description of testing for Chlamydia trachomatis in healthcare and nonhealthcare settings outside Genitourinary Medicine clinics in England and allowed a detailed analysis of positivity by age and ethnic group. Considerable heterogeneity exists and local health service commissioners need to ensure that the implementation of chlamydial screening reflects these differences

    Ultra-endurance athletic performance suggests that energetics drive human morphological thermal adaptation

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    Both extinct and extant hominin populations display morphological features consistent with Bergmann's and Allen's Rules. However, the functional implications of the morphologies described by these ecological laws are poorly understood. We examined this through the lens of endurance running. Previous research concerning endurance running has focused on locomotor energetic economy. We considered a less-studied dimension of functionality, thermoregulation. The performance of male ultra-marathon runners (n = 88) competing in hot and cold environments was analysed with reference to expected thermoregulatory energy costs and the optimal morphologies predicted by Bergmann's and Allen's Rules. Ecogeographical patterning supporting both principles was observed in thermally challenging environments. Finishers of hot-condition events had significantly longer legs than finishers of cold-condition events. Furthermore, hot-condition finishers had significantly longer legs than those failing to complete hot-condition events. A degree of niche-picking was evident; athletes may have tailored their event entry choices in accordance with their previous race experiences. We propose that the interaction between prolonged physical exertion and hot or cold climates may induce powerful selective pressures driving morphological adaptation. The resulting phenotypes reduce thermoregulatory energetic expenditure, allowing diversion of energy to other functional outcomes such as faster running

    Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B

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    Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet or substellar companion has yet been detected in polarized light. With the advent of high contrast imaging spectro-polarimeters such as GPI and SPHERE, such a detection may now be possible with careful treatment of instrumental polarization. In this paper, we present 28 minutes of H-band GPI polarimetric observations of the benchmark T5.5 companion HD 19467 B. We detect no polarization signal from the target, and place an upper limit on the degree of linear polarization of p_(CL99.73%) ⩽ 2.4%. We discuss our results in the context of T dwarf cloud models and photometric variability

    Using the Gerchberg-Saxton algorithm to reconstruct non-modulated pyramid wavefront sensor measurements

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    Adaptive optics (AO) is a technique to improve the resolution of ground-based telescopes by correcting, in real-time, optical aberrations due to atmospheric turbulence and the telescope itself. With the rise of Giant Segmented Mirror Telescopes (GSMT), AO is needed more than ever to reach the full potential of these future observatories. One of the main performance drivers of an AO system is the wavefront sensing operation, consisting of measuring the shape of the above mentioned optical aberrations. Aims. The non-modulated pyramid wavefront sensor (nPWFS) is a wavefront sensor with high sensitivity, allowing the limits of AO systems to be pushed. The high sensitivity comes at the expense of its dynamic range, which makes it a highly non-linear sensor. We propose here a novel way to invert nPWFS signals by using the principle of reciprocity of light propagation and the Gerchberg-Saxton (GS) algorithm. We test the performance of this reconstructor in two steps: the technique is first implemented in simulations, where some of its basic properties are studied. Then, the GS reconstructor is tested on the Santa Cruz Extreme Adaptive optics Laboratory (SEAL) testbed located at the University of California Santa Cruz. This new way to invert the nPWFS measurements allows us to drastically increase the dynamic range of the reconstruction for the nPWFS, pushing the dynamics close to a modulated PWFS. The reconstructor is an iterative algorithm requiring heavy computational burden, which could be an issue for real-time purposes in its current implementation. However, this new reconstructor could still be helpful in the case of many wavefront control operations. This reconstruction technique has also been successfully tested on the Santa Cruz Extreme AO Laboratory (SEAL) bench where it is now used as the standard way to invert nPWFS signal

    Comparing helpful and hindering processes in good and poor outcome cases : a qualitative metasynthesis of eight Hermeneutic Single Case Efficacy Design studies

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    Objective: We tested qualitative metasynthesis of a series of Hermeneutic Single Case Efficacy Design (HSCED) studies as a method for comparing within-session processes that may explain good and poor therapeutic outcome. Method: We selected eight HSCED studies according to change in clients' scores on the Strathclyde Inventory (SI), a brief self-report instrument used to measure outcome in person-centered psychotherapy. Four of the case studies investigated the experience of clients whose pre-post change in SI scores showed improvement by the end of therapy, and the other four focused on clients whose change in SI scores indicated deterioration. We conducted a qualitative metasynthesis, adopting a generic descriptive-interpretive approach to analyze and compare the data generated by the HSCED studies. Results: In contrast to improvers, deteriorators appeared to be less ready to engage in therapeutic work at the beginning of therapy, and found the process more difficult; their therapists were less able to respond to these difficulties in a responsive, empathic manner; deteriorators were less able to cope successfully with changes of therapist and, eventually, gave up on therapy. Conclusion: We found that our qualitative metasynthesis of a series of HSCED studies produced a plausible explanation for the contrasting outcomes that occurred

    Constraints on the architecture of the HD 95086 planetary system with the Gemini Planet Imager

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    We present astrometric monitoring of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager between 2013 and 2016. A small but significant position angle change is detected at constant separation; the orbital motion is confirmed with literature measurements. Efficient Monte Carlo techniques place preliminary constraints on the orbital parameters of HD 95086 b. With 68% confidence, a semimajor axis of 61.7^{+20.7}_{-8.4} au and an inclination of 153.0^{+9.7}_{-13.5} deg are favored, with eccentricity less than 0.21. Under the assumption of a co-planar planet-disk system, the periastron of HD 95086 b is beyond 51 au with 68% confidence. Therefore HD 95086 b cannot carve the entire gap inferred from the measured infrared excess in the SED of HD 95086. We use our sensitivity to additional planets to discuss specific scenarios presented in the literature to explain the geometry of the debris belts. We suggest that either two planets on moderately eccentric orbits or three to four planets with inhomogeneous masses and orbital properties are possible. The sensitivity to additional planetary companions within the observations presented in this study can be used to help further constrain future dynamical simulations of the planet-disk system.Comment: Accepted for publication in ApJ
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