7,384 research outputs found

    Cost-effectiveness of Microsoft Academic Graph with machine learning for automated study identification in a living map of coronavirus disease 2019 (COVID-19) research

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    BACKGROUND: Conventionally, searching for eligible articles to include in systematic reviews and maps of research has relied primarily on information specialists conducting Boolean searches of multiple databases and manually processing the results, including deduplication between these multiple sources. Searching one, comprehensive source, rather than multiple databases, could save time and resources. Microsoft Academic Graph (MAG) is potentially such a source, containing a network graph structure which provides metadata that can be exploited in machine learning processes. Research is needed to establish the relative advantage of using MAG as a single source, compared with conventional searches of multiple databases. This study sought to establish whether: (a) MAG is sufficiently comprehensive to maintain our living map of coronavirus disease 2019 (COVID-19) research; and (b) eligible records can be identified with an acceptably high level of specificity. METHODS: We conducted a pragmatic, eight-arm cost-effectiveness analysis (simulation study) to assess the costs, recall and precision of our semi-automated MAG-enabled workflow versus conventional searches of MEDLINE and Embase (with and without machine learning classifiers, active learning and/or fixed screening targets) for maintaining a living map of COVID-19 research. Resource use data (time use) were collected from information specialists and other researchers involved in map production. RESULTS: MAG-enabled workflows dominated MEDLINE-Embase workflows in both the base case and sensitivity analyses. At one month (base case analysis) our MAG-enabled workflow with machine learning, active learning and fixed screening targets identified n=469 more new, eligible articles for inclusion in our living map – and cost £3,179 GBP ($5,691 AUD) less – than conventional MEDLINE-Embase searches without any automation or fixed screening targets. CONCLUSIONS: MAG-enabled continuous surveillance workflows have potential to revolutionise study identification methods for living maps, specialised registers, databases of research studies and/or collections of systematic reviews, by increasing their recall and coverage, whilst reducing production costs

    Fatigue limit of recycled aggregate concrete

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    This paper presents the main results of the research carried out to obtain the fatigue limit of concrete incorporating recycled aggregate from concrete. In this research, recycled aggregate concretes with partial and total coarse aggregate replacement and control concretes with different increasing water/cement ratios have been cast to study the material’s behavior in response to repeated compressive loads. The results show that, for the same water/cement ratio, the recycled aggregate concretes present a loss of stiffness higher than the control concrete. Furthermore, the use of recycled aggregate in concrete implies a reduction of the fatigue life. These differences are increased for low water/cement ratios, as in this case the main factor is the lower strength capacity of the aggregate. From the results obtained, recommendable mixtures for recycled aggregates exposed to fatigue loads are proposed

    Arrested Protein Synthesis Increases Persister-Like Cell Formation

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    Biofilms are associated with a wide variety of bacterial infections and pose a serious problem in clinical medicine due to their inherent resilience to antibiotic treatment. Within biofilms, persister cells comprise a small bacterial subpopulation that exhibits multidrug tolerance to antibiotics without undergoing genetic change. The low frequency of persister cell formation makes it difficult to isolate and study persisters, and bacterial persistence is often attributed to a quiescent metabolic state induced by toxins that are regulated through toxin-antitoxin systems. Here we mimic toxins via chemical pretreatments to induce high levels of persistence (10 to 100%) from an initial population of 0.01%. Pretreatment of Escherichia coli with (i) rifampin, which halts transcription, (ii) tetracycline, which halts translation, and (iii) carbonyl cyanide m-chlorophenylhydrazone, which halts ATP synthesis, all increased persistence dramatically. Using these compounds, we demonstrate that bacterial persistence results from halted protein synthesis and from environmental cues

    Influences of dynamical disruptions on the evolution of pulsars in globular clusters

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    By comparing the physical properties of pulsars hosted by core-collapsed (CCed) and non-core-collapsed (Non-CCed) globular clusters (GCs), we find that pulsars in CCed GCs rotate significantly slower than their counterparts in Non-CCed GCs. Additionally, radio luminosities at 1.4 GHz in CCed GCs are higher. These findings are consistent with the scenario that dynamical interactions in GCs can interrupt angular momentum transfer processes and surface magnetic field decay during the recycling phase. Our results suggest that such effects in CCed GCs are stronger due to more frequent disruptions of compact binaries. This is further supported by the observation that both estimated disruption rates and the fraction of isolated pulsars are predominantly higher in CCed GCs.Comment: 9 pages, 8 figures, 3 tables, Accepted in MNRA
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