688 research outputs found

    Formation of the Flatreef deposit, northern Bushveld, by hydrodynamic and hydromagmatic processes

    Get PDF
    New lithological and whole rock compositional data show that the main platinum-group element (PGE) horizons of the Flatreef succession show strong compositional similarities to the Merensky and Bastard reefs of the western Bushveld Complex (WBC), notably in terms of many immobile and incompatible minor and trace elements such as TiO2, Zr, Y, and REE. However, Al2O3, CaO, and Na2O contents are markedly lower in the Flatreef, whereas MgO contents are higher. In view of broadly similar silicate mineral compositions in the Flatreef and the WBC reefs, we suggest that the major element compositional differences between the rocks are largely due to higher modal proportions of orthopyroxene and olivine and lower proportions of plagioclase in the Flatreef. The thickness of the mineralised interval is much greater in the Flatreef than in the WBC (several 10 s of m vs ~ 1 m) and the abundance of sulfides in the Flatreef is typically somewhat higher (on average ~ 1.5% vs ~ 1%). These data, complemented by textural observations, are interpreted to reflect enhanced hydrodynamic crystal sorting accompanied by percolation of sulfide melt through incompletely solidified cumulates. Further genetic constraints are provided by metal data: The concentration of Ni (~ 3000 ppm) in the Flatreef is broadly similar to that in the Merensky Reef of the WBC, but Cu contents are markedly higher (average ~ 1500 ppm vs 700 ppm in the WBC). The concentrations of most PGE are slightly lower (Flatreef ~ 1.5–2 ppm Pt, ~ 100–150 ppb Rh; WBC MR 3.7 ppm Pt, 240 ppb Rh), but Pd has broadly similar contents (Flatreef ~ 1.2–2 ppm; WBC MR 1.54 ppm). The relatively high Cu content of the Flatreef is interpreted as a result of assimilation of Cu sulfides from the sedimentary floor rocks. The reason for the enrichment of Pd relative to Pt, especially in the basal rocks, remains unclear. It could reflect mobilisation of Pd via a fluid phase from the country rocks or the interior of the intrusion, relatively enhanced partitioning of Pd into the sulfides, or relative Pt depletion of the earliest magma pulses in response to Pt alloy fractionation triggered by contamination with reducing country rocks

    CareSearch: finding and evaluating Australia's missing palliative care literature

    Get PDF
    BACKGROUND: Palliative care is an evolving specialty with a growing evidence base. However, evidence is less accessible than it could be with a lower than average conversion of conference abstracts to articles in peer-reviewed journals and the need for more accessible tools to support evidence-based practice (EBP) in palliative care. The CareSearch project involved identifying, collecting and evaluating Australia's "grey" palliative care literature and identifying international published literature missing from the electronic indexing systems. The literature was then catalogued and made publicly available through the CareSearch website. RESULTS: To date over 2,500 items have been included in the CareSearch database and can be accessed and searched through a publicly available website. Nearly 2,000 items are conference abstracts and 178 are theses or government, organisational and planning documents. A further 410 items relate to articles from palliative journals that are not indexed on a major bibliographic database. The website also provides tools and facilities to support palliative care practice and research. CONCLUSION: CareSearch is a new evidence resource for palliative practitioners, educators and researchers. The palliative community now has access to a more comprehensive literature base as well as a resource that supports the integration of knowledge into practice. This specialised data repository enables users to access information on the body of work that has shaped palliative care development and prevents the potential loss or duplication of research work. It also provides a template for other emerging disciplines to use in capturing their literature and evidence

    Brief Report: Correlates of Quality of Life-related Outcomes in Breast Cancer Patients Participating in the Pathfinders Pilot Study

    Get PDF
    In a pilot study, participation in the Pathfinders program was associated with reductions in distress and despair and improvements in quality of life (QOL) among advanced breast cancer patients. This paper explores the relationship between psychosocial resources invoked through the Pathfinders intervention and outcomes

    Effects of neutron irradiation on the brittle to ductile transition in single crystal tungsten

    Get PDF
    Only limited data exist on the effect of neutron irradiation on the brittle to ductile transition (BDT) in tungsten. This work investigates the increase in brittle to ductile transition temperature (BDTT) following neutron irradiation to 1.67 displacements per atom, using four-point bend tests over a range of temperatures (623–1173 K) and strain rates (3.5 × 10−7 - 2.5 × 10−5 s−1). The BDTT was found to increase by 500 K after irradiation. The activation energy for the BDT was determined using Arrhenius analysis of the four-point bend tests. Nanoindentation strain-rate jump tests were used to characterise the activation volume for dislocation motion. These were quantified as 1.05 eV and 18 b3 respectively, very close to values found for unirradiated tungsten. This suggests that kink-pair formation is the controlling mechanism for the BDT before and after irradiation. This work also carries out a unique verification of inventory-code-modelling (via FISPACT-II) of transmutation of tungsten to rhenium and osmium under neutron irradiation using two independent techniques (X-ray and gamma-ray spectroscopy). These results show that modelling can correctly predict this transmutation, provided that an accurate neutron spectrum is used. This is a critical result given the widespread use of inventory codes such as FISPACT-II, and the associated nuclear data libraries, for modelling transmutation of tungsten

    Effects of neutron irradiation on the brittle to ductile transition in single crystal tungsten

    Get PDF
    Only limited data exist on the effect of neutron irradiation on the brittle to ductile transition (BDT) in tungsten. This work investigates the increase in brittle to ductile transition temperature (BDTT) following neutron irradiation to 1.67 displacements per atom, using four-point bend tests over a range of temperatures (623-1173 K) and strain rates (3.5 x 107^{-7}- 2.5 x 105^{-5} s1^{-1}). The BDTT was found to increase by 500 K after irradiation. The activation energy for the BDT was determined using Arrhenius analysis of the four-point bend tests. Nanoindentation strain-rate jump tests were used to characterise the activation volume for dislocation motion. These were quantified as 1.05 eV and 4.6 b³ respectively, very close to values found for unirradiated tungsten. This suggests that kink-pair formation is the controlling mechanism for the BDT before and after irradiation. This work also carries out a unique verification of inventory-code-modelling (via FISPACT-II) of transmutation of tungsten to rhenium and osmium under neutron irradiation using two independent techniques (X-ray and gamma-ray spectroscopy). These results show that modelling can correctly predict this transmutation, provided that an accurate neutron spectrum is used. This is a critical result given the widespread use of inventory codes such as FISPACT-II, and the associated nuclear data libraries, for modelling transmutation of tungsten

    Implementing Electronic Tablet-Based Education of Acute Care Patients

    Get PDF
    Poor education-related discharge preparedness for patients with heart failure is believed to be a major cause of avoidable rehospitalizations. Technology-based applications offer innovative educational approaches that may improve educational readiness for patients in both inpatient and outpatient settings; however, a number of challenges exist when implementing electronic devices in the clinical setting. Implementation challenges include processes for "on-boarding" staff, mediating risks of cross-contamination with patients' device use, and selling the value to staff and health system leaders to secure the investment in software, hardware, and system support infrastructure. Strategies to address these challenges are poorly described in the literature. The purpose of this article is to present a staff development program designed to overcome challenges in implementing an electronic, tablet-based education program for patients with heart failure

    Phase 2 pilot study of Pathfinders: a psychosocial intervention for cancer patients

    Get PDF
    Pathfinders is a multi-faceted psychosocial care program for cancer patients; it was developed in community oncology and adapted to the academic oncology setting. This prospective, single-arm, phase 2 pilot study examined the acceptability and feasibility of Pathfinders for women with metastatic breast cancer

    Multi-Target Prediction: A Unifying View on Problems and Methods

    Full text link
    Multi-target prediction (MTP) is concerned with the simultaneous prediction of multiple target variables of diverse type. Due to its enormous application potential, it has developed into an active and rapidly expanding research field that combines several subfields of machine learning, including multivariate regression, multi-label classification, multi-task learning, dyadic prediction, zero-shot learning, network inference, and matrix completion. In this paper, we present a unifying view on MTP problems and methods. First, we formally discuss commonalities and differences between existing MTP problems. To this end, we introduce a general framework that covers the above subfields as special cases. As a second contribution, we provide a structured overview of MTP methods. This is accomplished by identifying a number of key properties, which distinguish such methods and determine their suitability for different types of problems. Finally, we also discuss a few challenges for future research

    Multitask training promotes automaticity of a fundamental laparoscopic skill without compromising the rate of skill learning.

    Get PDF
    A defining characteristic of expertise is automated performance of skills, which frees attentional capacity to better cope with some common intraoperative stressors. There is a paucity of research on how best to foster automated performance by surgical trainees. This study examined the use of a multitask training approach to promote automated, robust laparoscopic skills.Eighty-one medical students completed training of a fundamental laparoscopic task in either a traditional single-task training condition or a novel multitask training condition. Following training, participants' laparoscopic performance was tested in a retention test, two stress transfer tests (distraction and time pressure) and a secondary task test, which was included to evaluate automaticity of performance. The laparoscopic task was also performed as part of a formal clinical examination (OSCE).The training groups did not differ in the number of trials required to reach task proficiency (p = .72), retention of skill (ps > .45), or performance in the clinical examination (p = .14); however, the groups did differ with respect to the secondary task (p = .016). The movement efficiency (number of hand movements) of single-task trainees, but not multitask trainees, was negatively affected during the secondary task test. The two stress transfer tests had no discernable impact on the performance of either training group.Multitask training was not detrimental to the rate of learning of a fundamental laparoscopic skill and added value by providing resilience in the face of a secondary task load, indicative of skill automaticity. Further work is needed to determine the extent of the clinical utility afforded by multitask training

    Professionalism, Golf Coaching and a Master of Science Degree: A commentary

    Get PDF
    As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues
    corecore