41,810 research outputs found

    Second-order post-Hartree-Fock perturbation theory for the electron current

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    Based on the super-fermion representation of quantum kinetic equations we develop nonequilibrium, post-Hartree-Fock many-body perturbation theory for the current through a region of interacting electrons. We apply the theory to out of equilibrium Anderson model and discuss practical implementation of the approach. Our calculations show that nonequilibrium electronic correlations may produce significant quantitative and qualitative corrections to mean-field electronic transport properties. We find that the nonequilibrium leads to enhancement of electronic correlations

    Effectiveness, cost-effectiveness and cost-benefit of a single annual professional intervention for the prevention of childhood dental caries in a remote rural Indigenous community

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    Background The aim of the study is to reduce the high prevalence of tooth decay in children in a remote, rural Indigenous community in Australia, by application of a single annual dental preventive intervention. The study seeks to (1) assess the effectiveness of an annual oral health preventive intervention in slowing the incidence of dental caries in children in this community, (2) identify the mediating role of known risk factors for dental caries and (3) assess the cost-effectiveness and cost-benefit of the intervention. Methods/design The intervention is novel in that most dental preventive interventions require regular re-application, which is not possible in resource constrained communities. While tooth decay is preventable, self-care and healthy habits are lacking in these communities, placing more emphasis on health services to deliver an effective dental preventive intervention. Importantly, the study will assess cost-benefit and cost-effectiveness for broader implementation across similar communities in Australia and internationally. Discussion There is an urgent need to reduce the burden of dental decay in these communities, by implementing effective, cost-effective, feasible and sustainable dental prevention programs. Expected outcomes of this study include improved oral and general health of children within the community; an understanding of the costs associated with the intervention provided, and its comparison with the costs of allowing new lesions to develop, with associated treatment costs. Findings should be generalisable to similar communities around the world. The research is registered with the Australian New Zealand Clinical Trials Registry (ANZCTR), registration number ACTRN12615000693527; date of registration: 3rd July 2015

    Hydropyrolysis: implications for radiocarbon pre-treatment and characterization of Black Carbon

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    Charcoal is the result of natural and anthropogenic burning events, when biomass is exposed to elevated temperatures under conditions of restricted oxygen. This process produces a range of materials, collectively known as pyrogenic carbon, the most inert fraction of which is known as Black Carbon (BC). BC degrades extremely slowly, and is resistant to diagenetic alteration involving the addition of exogenous carbon making it a useful target substance for radiocarbon dating particularly of more ancient samples, where contamination issues are critical. We present results of tests using a new method for the quantification and isolation of BC, known as hydropyrolysis (hypy). Results show controlled reductive removal of non-BC organic components in charcoal samples, including lignocellulosic and humic material. The process is reproducible and rapid, making hypy a promising new approach not only for isolation of purified BC for 14C measurement but also in quantification of different labile and resistant sample C fractions

    Demographic characteristics of exploited tropical lutjanids: a comparative analysis

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    Demographic parameters from seven exploited coral reef lutjanid species were compared as a case study of the implications of intrafamily variation in life histories for multispecies harvest management. Modal lengths varied by 4 cm among four species (Lutjanus fulviflamma, L. vitta, L. carponotatus, L. adetii), which were at least 6 cm smaller than the modal lengths of the largest species (L. gibbus, Symphorus nematophorus, Aprion virescens). Modal ages, indicating ages of full selection to fishing gear, were 10 years or less for all species, but maximum ages ranged from 12 (L. gibbus) to 36 years (S. nematophorus). Each species had a unique growth pattern, with differences in length-at-age and mean asymptotic fork length (L∞), but smaller species generally grew fast during the first 1–2 years of life and larger species grew more slowly over a longer period. Total mortality rates varied among species; L. gibbus had the highest mortality and L. fulviflamma, the lowest mortality. The variability in life history strategies of these tropical lutjanids makes generalizations about lutjanid life histories difficult, but the fact that all seven had characteristics that would make them particularly vulnerable to fishing indicates that harvest of tropical lutjanids should be managed with caution

    Perceptions of trends in Seychelles artisanal trap fisheries: comparing catch monitoring, underwater visual census and fishers' knowledge

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    Fisheries scientists and managers are increasingly engaging with fishers' knowledge (FK) to provide novel information and improve the legitimacy of fisheries governance. Disputes between the perceptions of fishers and scientists can generate conflicts for governance, but can also be a source of new perspectives or understandings. This paper compares artisanal trap fishers' reported current catch rates with landings data and underwater visual census (UVC). Fishers' reports of contemporary 'normal' catch per day tended to be higher than recent median landings records. However, fishers' reports of 'normal' catch per trap were not significantly different from the median CPUE calculated from landings data, and reports of 'good' and 'poor' catch rates were indicative of variability observed in landings data. FK, landings and UVC data all gave different perspectives of trends over a ten-year period. Fishers' perceptions indicated greater declines than statistical models fitted to landings data, while UVC evidence for trends varied between sites and according to the fish assemblage considered. Divergence in trend perceptions may have resulted from differences in the spatial, temporal or taxonomic focus of each dataset. Fishers may have experienced and understood behavioural changes and increased fishing power, which may have obscured declines from landings data. Various psychological factors affect memory and recall, and may have affected these memory-based estimates of trends, while different assumptions underlying the analysis of both interview data and conventional scientific data could also have led to qualitatively different trend perceptions. Differing perspectives from these three data sources illustrate both the potential for 'cognitive conflicts' between stakeholders who do not rely on the same data sources, as well as the importance of multiple information sources to understand dynamics of fisheries. Collaborative investigation of such divergence may facilitate learning and improve fisheries governance

    Competency and Capability: Imperative for Nurse Practitioner Education

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    Objective The objective of this study was to conduct research to inform the development of standards for nurse practitioner education in Australia and New Zealand and to contribute to the international debate on nurse practitioner practice. Setting The research was conducted in all states of Australia where the nurse practitioner is authorised and in New Zealand Subjects The research was informed by multiple data sources including nurse practitioner program curriculae documents from all relevant universities in Australia and New Zealand, interviews with academic convenors of these programs and interviews with nurse practitioners. Primary argument Findings from this research include support for masters level of education as preparation for the nurse practitioner. These programs need to have a strong clinical learning component and in-depth education for the sciences of specialty practice. Additionally an important aspect of education for the nurse practitioner is the centrality of student directed and flexible learning models. This approach is well supported by the literature on capability. Conclusions There is agreement in the literature about the lack of consistent standards in nurse practitioner practice, education and nomenclature. The findings from this research contribute to the international debate in this area and bring research informed standards to nurse practitioner education in Australia and New Zealand

    MI as a predictor of students’ performance in reading competency

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    The purpose of this study was to examine whether performance in MI could predict the performance in reading competency. The other objectives were to identify the components of MI which are correlated with the reading test scores, and to determine the relationship between the multiple intelligences and reading proficiency. A descriptive and ex post facto design was employed to ascertain relationships among the variables. The participants were 128 randomly chosen pre-university students (grade12, 18-19 years old) of both genders studying in Tehran in the academic year 2008-2009. Three instruments were utilized in this study: 1) a demographic questionnaire; 2) the Persian version of Mckenzie’s MI Inventory; and 3) a standardized reading proficiency test which was selected from retrieved paper-based TOEFL® tests. Results of the correlation analysis revealed no significant relationship between the two variables of MI and reading scores of the students. Furthermore, the results of the correlation analysis revealed that there was a low significant, negative relationship between musical-rhythmic intelligence and reading which suggests that when the reading score of a student increases, musical-rhythmic intelligence of the same student decreases and vice versa. Overall, three categories of MI (musical-rhythmic, verbal-linguistic, bodily-kinesthetic) were found to be predictive of reading proficiency

    Cylindrical, periodic surface lattice — theory, dispersion analysis, and experiment

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    A two-dimensional surface lattice of cylindrical topology obtained via perturbing the inner surface of a cylinder is considered. Periodic perturbations of the surface lead to observation of high-impedance, dielectric-like media and resonant coupling of surface and non-propagating volume fields. This allows synthesis of tailored-for-purpose "coating" material with dispersion suitable, for instance, to mediate a Cherenkov type interaction. An analytical model of the lattice is discussed and coupled-wave equations are derived. Variations of the lattice dispersive properties with variation of parameters are shown, illustrating the tailoring of the structure's electromagnetic properties. Experimental results are presented showing agreement with the theoretical model

    The civil and family law needs of Indigenous people in Victoria

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    This report identifies the most pressing legal needs of Indigenous Victorians, which involve housing, discrimination and debt.The report presents key findings and recommendations of research conducted in 2012- 2013 by the Indigenous Legal Needs Project (ILNP) in Victoria. The ILNP is a national project. Its aims are to:identify and analyse the legal needs of Indigenous communities in non-criminal areas of law (including discrimination, housing and tenancy, child protection, employment, credit and debt, wills and estates, and consumer-related matters); and provide an understanding of how legal service delivery might work more effectively to address identified civil and family law needs of Indigenous communities. ILNP research is intended to benefit Indigenous people by improving access to civil and family law justice

    Linking individual phenotype to density-dependent population growth: the influence of body size on the population dynamics of malaria vectors

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    Understanding the endogenous factors that drive the population dynamics of malaria mosquitoes will facilitate more accurate predictions about vector control effectiveness and our ability to destabilize the growth of either low- or high-density insect populations. We assessed whether variation in phenotypic traits predict the dynamics of Anopheles gambiae sensu lato mosquitoes, the most important vectors of human malaria. Anopheles gambiae dynamics were monitored over a six-month period of seasonal growth and decline. The population exhibited density-dependent feedback, with the carrying capacity being modified by rainfall (97% wAICc support). The individual phenotypic expression of the maternal (p = 0.0001) and current (p = 0.040) body size positively influenced population growth. Our field-based evidence uniquely demonstrates that individual fitness can have population-level impacts and, furthermore, can mitigate the impact of exogenous drivers (e.g. rainfall) in species whose reproduction depends upon it. Once frontline interventions have suppressed mosquito densities, attempts to eliminate malaria with supplementary vector control tools may be attenuated by increased population growth and individual fitness
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