351 research outputs found

    Machine learning with the hierarchy‐of‐hypotheses (HoH) approach discovers novel pattern in studies on biological invasions

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    Research synthesis on simple yet general hypotheses and ideas is challenging in scientific disciplines studying highly context‐dependent systems such as medical, social, and biological sciences. This study shows that machine learning, equation‐free statistical modeling of artificial intelligence, is a promising synthesis tool for discovering novel patterns and the source of controversy in a general hypothesis. We apply a decision tree algorithm, assuming that evidence from various contexts can be adequately integrated in a hierarchically nested structure. As a case study, we analyzed 163 articles that studied a prominent hypothesis in invasion biology, the enemy release hypothesis. We explored if any of the nine attributes that classify each study can differentiate conclusions as classification problem. Results corroborated that machine learning can be useful for research synthesis, as the algorithm could detect patterns that had been already focused in previous narrative reviews. Compared with the previous synthesis study that assessed the same evidence collection based on experts' judgement, the algorithm has newly proposed that the studies focusing on Asian regions mostly supported the hypothesis, suggesting that more detailed investigations in these regions can enhance our understanding of the hypothesis. We suggest that machine learning algorithms can be a promising synthesis tool especially where studies (a) reformulate a general hypothesis from different perspectives, (b) use different methods or variables, or (c) report insufficient information for conducting meta‐analyses

    The Grammar of the Reporting of Qualitative Research

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    The utility of research has been discussed in many arenas and for many reasons over the past few years. Given that most research is disseminated via reports and papers, the medium through which research is used has also been under scrutiny. Often, the quality of reporting has been criticised. This is particularly evident in health-related areas where many reporting guidelines have been developed. While some of this debate has surfaced in social science disciplines, there has not been the same level of activity in developing guidelines. One exception is REPOSE - developed for use in educational research. The authors of these guidelines found that some aspects of research were inadequately reported and that authors’ guidance given by journals does not, in the main, specify how the research itself should be reported

    Using framework-based synthesis for conducting reviews of qualitative studies

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    Framework analysis is a technique used for data analysis in primary qualitative research. Recent years have seen its being adapted to conduct syntheses of qualitative studies. Framework-based synthesis shows considerable promise in addressing applied policy questions. An innovation in the approach, known as 'best fit' framework synthesis, has been published in BMC Medical Research Methodology this month. It involves reviewers in choosing a conceptual model likely to be suitable for the question of the review, and using it as the basis of their initial coding framework. This framework is then modified in response to the evidence reported in the studies in the reviews, so that the final product is a revised framework that may include both modified factors and new factors that were not anticipated in the original model. 'Best fit' framework-based synthesis may be especially suitable in addressing urgent policy questions where the need for a more fully developed synthesis is balanced by the need for a quick answer

    Cost-Effectiveness of a national initiative to improve hand hygiene compliance using the outcome of healthcare associated staphylococcus aureus bacteraemia

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    © 2016 Graves et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background The objective is to estimate the incremental cost-effectiveness of the Australian National Hand Hygiene Inititiave implemented between 2009 and 2012 using healthcare associated Staphylococcus aureus bacteraemia as the outcome. Baseline comparators are the eight existing state and territory hand hygiene programmes. The setting is the Australian public healthcare system and 1,294,656 admissions from the 50 largest Australian hospitals are included. Methods The design is a cost-effectiveness modelling study using a before and after quasi-experimental design. The primary outcome is cost per life year saved from reduced cases of healthcare associated Staphylococcus aureus bacteraemia, with cost estimated by the annual on-going maintenance costs less the costs saved from fewer infections. Data were harvested from existing sources or were collected prospectively and the time horizon for the model was 12 months, 2011-2012. Findings No useable pre-implementation Staphylococcus aureus bacteraemia data were made available from the 11 study hospitals in Victoria or the single hospital in Northern Territory leaving 38 hospitals among six states and territories available for cost-effectiveness analyses. Total annual costs increased by 2,851,475forareturnof96yearsoflifegivinganincrementalcost−effectivenessratio(ICER)of2,851,475 for a return of 96 years of life giving an incremental cost-effectiveness ratio (ICER) of 29,700 per life year gained. Probabilistic sensitivity analysis revealed a 100% chance the initiative was cost effective in the AustralianCapital Territory and Queensland, with ICERs of 1,030and1,030 and 8,988 respectively. There was an 81% chance it was cost effective in New South Wales with an ICER of 33,353,a2633,353, a 26% chance for South Australia with an ICER of 64,729 and a 1% chance for Tasmania and Western Australia. The 12 hospitals in Victoria and the Northern Territory incur annual on-going maintenance costs of 1.51M;noinformationwasavailabletodescribecostsavingsorhealthbenefits.ConclusionsTheAustralianNationalHandHygieneInitiativewascost−effectiveagainstanAustralianthresholdof1.51M; no information was available to describe cost savings or health benefits. Conclusions The Australian National Hand Hygiene Initiative was cost-effective against an Australian threshold of 42,000 per life year gained. The return on investment varied among the states and territories of Australia

    Improved algebraic cryptanalysis of QUAD, Bivium and Trivium via graph partitioning on equation systems

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    We present a novel approach for preprocessing systems of polynomial equations via graph partitioning. The variable-sharing graph of a system of polynomial equations is defined. If such graph is disconnected, then the corresponding system of equations can be split into smaller ones that can be solved individually. This can provide a tremendous speed-up in computing the solution to the system, but is unlikely to occur either randomly or in applications. However, by deleting certain vertices on the graph, the variable-sharing graph could be disconnected in a balanced fashion, and in turn the system of polynomial equations would be separated into smaller systems of near-equal sizes. In graph theory terms, this process is equivalent to finding balanced vertex partitions with minimum-weight vertex separators. The techniques of finding these vertex partitions are discussed, and experiments are performed to evaluate its practicality for general graphs and systems of polynomial equations. Applications of this approach in algebraic cryptanalysis on symmetric ciphers are presented: For the QUAD family of stream ciphers, we show how a malicious party can manufacture conforming systems that can be easily broken. For the stream ciphers Bivium and Trivium, we nachieve significant speedups in algebraic attacks against them, mainly in a partial key guess scenario. In each of these cases, the systems of polynomial equations involved are well-suited to our graph partitioning method. These results may open a new avenue for evaluating the security of symmetric ciphers against algebraic attacks

    Using a theory of planned behaviour framework to explore hand hygiene beliefs at the '5 critical moments' among Australian hospital-based nurses 59

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    © 2015 White et al. Background: Improving hand hygiene among health care workers (HCWs) is the single most effective intervention to reduce health care associated infections in hospitals. Understanding the cognitive determinants of hand hygiene decisions for HCWs with the greatest patient contact (nurses) is essential to improve compliance. The aim of this study was to explore hospital-based nurses ' beliefs associated with performing hand hygiene guided by the World Health Organization's (WHO) 5 critical moments. Using the belief-base framework of the Theory of Planned Behaviour, we examined attitudinal, normative, and control beliefs underpinning nurses' decisions to perform hand hygiene according to the recently implemented national guidelines. Methods: Thematic content analysis of qualitative data from focus group discussions with hospital-based registered nurses from 5 wards across 3 hospitals in Queensland, Australia. Results: Important advantages (protection of patient and self), disadvantages (time, hand damage), referents (supportive: patients, colleagues; unsupportive: some doctors), barriers (being too busy, emergency situations), and facilitators (accessibility of sinks/products, training, reminders) were identified. There was some equivocation regarding the relative importance of hand washing following contact with patient surroundings. Conclusions: The belief base of the theory of planned behaviour provided a useful framework to explore systematically the underlying beliefs of nurses ' hand hygiene decisions according to the 5 critical moments, allowing comparisons with previous belief studies. A commitment to improve nurses' hand hygiene practice across the 5 moments should focus on individual strategies to combat distraction from other duties, peer-based initiatives to foster a sense of shared responsibility, and management-driven solutions to tackle staffing and resource issues. Hand hygiene following touching a patient's surroundings continues to be reported as the most neglected opportunity for compliance

    RAMESES publication standards: realist syntheses

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    PMCID: PMC3558331This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Interpretation of Experimental J^PC Exotic Signals

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    We investigate theoretical interpretations of the 1.4 GeV J^PC exotic resonance reported by the E852 collaboration. It is argued that interpretation in terms of a hybrid meson is untenable. A K-matrix analysis shows that the 1.4 GeV enhancement in the E852 eta pi data can be understood as an interference of a non-resonant Deck-type background and a resonance at 1.6 GeV. A final state rescattering calculation shows that the 1.6 GeV hybrid has a eta pi width which is bounded above by 57 \pm 14 MeV.Comment: 23 pages, LaTeX, 4 encapsulated postscript figures. Accepted for publication by Physical Review

    Baryogenesis from Primordial Blackholes after Electroweak Phase Transition

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    Incorporating a realistic model for accretion of ultra-relativistic particles by primordial blackholes (PBHs), we study the evolution of an Einstein-de Sitter universe consisting of PBHs embedded in a thermal bath from the epoch ∌10−33\sim 10^{-33} sec to ∌5×10−9\sim 5\times 10^{-9} sec. In this paper we use Barrow et al's ansatz to model blackhole evaporation in which the modified Hawking temperature goes to zero in the limit of the blackhole attaining a relic state with mass ∌mpl\sim m_{pl}. Both single mass PBH case as well as the case in which blackhole masses are distributed in the range 8×102−3×1058\times 10^2 - 3\times 10^5 gm have been considered in our analysis. Blackholes with mass larger than ∌105\sim 10^5 gm appear to survive beyond the electroweak phase transition and, therefore, successfully manage to create baryon excess via X−XˉX-\bar X emissions, averting the baryon number wash-out due to sphalerons. In this scenario, we find that the contribution to the baryon-to-entropy ratio by PBHs of initial mass mm is given by ∌ϔζ(m/1gm)−1\sim \epsilon \zeta (m/1 {gm})^{-1}, where Ï”\epsilon and ζ\zeta are the CP-violating parameter and the initial mass fraction of the PBHs, respectively. For Ï”\epsilon larger than ∌10−4\sim 10^{-4}, the observed matter-antimatter asymmetry in the universe can be attributed to the evaporation of PBHs.Comment: Latex2e file with seven figures included as postscript file
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