1,204 research outputs found

    Delineating Knowledge Domains in Scientific Domains in Scientific Literature using Machine Learning (ML)

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    The recent years have witnessed an upsurge in the number of published documents. Organizations are showing an increased interest in text classification for effective use of the information. Manual procedures for text classification can be fruitful for a handful of documents, but the same lack in credibility when the number of documents increases besides being laborious and time-consuming. Text mining techniques facilitate assigning text strings to categories rendering the process of classification fast, accurate, and hence reliable. This paper classifies chemistry documents using machine learning and statistical methods. The procedure of text classification has been described in chronological order like data preparation followed by processing, transformation, and application of classification techniques culminating in the validation of the results

    Outlier Edge Detection Using Random Graph Generation Models and Applications

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    Outliers are samples that are generated by different mechanisms from other normal data samples. Graphs, in particular social network graphs, may contain nodes and edges that are made by scammers, malicious programs or mistakenly by normal users. Detecting outlier nodes and edges is important for data mining and graph analytics. However, previous research in the field has merely focused on detecting outlier nodes. In this article, we study the properties of edges and propose outlier edge detection algorithms using two random graph generation models. We found that the edge-ego-network, which can be defined as the induced graph that contains two end nodes of an edge, their neighboring nodes and the edges that link these nodes, contains critical information to detect outlier edges. We evaluated the proposed algorithms by injecting outlier edges into some real-world graph data. Experiment results show that the proposed algorithms can effectively detect outlier edges. In particular, the algorithm based on the Preferential Attachment Random Graph Generation model consistently gives good performance regardless of the test graph data. Further more, the proposed algorithms are not limited in the area of outlier edge detection. We demonstrate three different applications that benefit from the proposed algorithms: 1) a preprocessing tool that improves the performance of graph clustering algorithms; 2) an outlier node detection algorithm; and 3) a novel noisy data clustering algorithm. These applications show the great potential of the proposed outlier edge detection techniques.Comment: 14 pages, 5 figures, journal pape

    Triggered or routine site monitoring visits for randomised controlled trials: results of TEMPER, a prospective, matched-pair study

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    Background/aims: In multi-site clinical trials, where trial data and conduct are scrutinised centrally with pre-specified triggers for visits to sites, targeted monitoring may be an efficient way to prioritise on-site monitoring. This approach is widely used in academic trials, but has never been formally evaluated. // Methods: TEMPER assessed the ability of targeted monitoring, as used in three ongoing phase III randomised multi-site oncology trials, to distinguish sites at which higher and lower rates of protocol and/or Good Clinical Practice violations would be found during site visits. Using a prospective, matched-pair design, sites that had been prioritised for visits after having activated ‘triggers’ were matched with a control (‘untriggered’) site, which would not usually have been visited at that time. The paired sites were visited within 4 weeks of each other, and visit findings are recorded and categorised according to the seriousness of the deviation. The primary outcome measure was the proportion of sites with ≥1 ‘Major’ or ‘Critical’ finding not previously identified centrally. The study was powered to detect an absolute difference of ≥30% between triggered and untriggered visits. A sensitivity analysis, recommended by the study’s blinded endpoint review committee, excluded findings related to re-consent. Additional analyses assessed the prognostic value of individual triggers and data from pre-visit questionnaires completed by site and trials unit staff. // Results: In total, 42 matched pairs of visits took place between 2013 and 2016. In the primary analysis, 88.1% of triggered visits had ≥1 new Major/Critical finding, compared to 81.0% of untriggered visits, an absolute difference of 7.1% (95% confidence interval −8.3%, +22.5%; p = 0.365). When re-consent findings were excluded, these figures reduced to 85.7% versus 59.5%, (difference = 26.2%, 95% confidence interval 8.0%, 44.4%; p = 0.007). Individual triggers had modest prognostic value but knowledge of the trial-related activities carried out by site staff may be useful. // Conclusion: Triggered monitoring approaches, as used in these trials, were not sufficiently discriminatory. The rate of Major and Critical findings was higher than anticipated, but the majority related to consent and re-consent with no indication of systemic problems that would impact trial-wide safety issues or integrity of the results in any of the three trials. Sensitivity analyses suggest triggered monitoring may be of potential use, but needs improvement and investigation of further central monitoring triggers is warranted. TEMPER highlights the need to question and evaluate methods in trial conduct, and should inform further developments in this area

    May Measurement Month (MMM) 2017: an analysis of blood pressure screening results in Bangladesh-South Asia

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    Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. Based on the findings of the non-communicable disease Risk Factors Survey Bangladesh 2010, the prevalence of hypertension in adults 25 years or older in Bangladesh is 20.1%. The Bangladesh Demographic Health Survey, 2011 showed that approximately 50% of those affected are unaware of their hypertensive condition. The May Measurement Month 2017 (MMM17) is a global initiative of the International Society of Hypertension (ISH) aimed at raising awareness of high BP. We participated in MMM17 to raise awareness of hypertension screening and identify those with elevated BP who were unaware, and those on treatment with still uncontrolled hypertension. Following the standard protocol designed by the ISH, we participated in MMM17, an opportunistic cross-sectional survey of volunteers aged ≥18. It was carried out in May 2017. BP measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. Data were collected from 35 screening sites in 33 districts in Bangladesh. Personnel from several government and non-government organizations volunteered in this huge event. A total of 11 418 individuals were screened during MMM17, of which 5401 (47.3%) were found to have hypertension. Of 8365 individuals not receiving anti-hypertensive medication, 2348 (28.1%) were hypertensive. Of 3053 individuals receiving anti-hypertensive medication, 1594 (52.2%) had uncontrolled BP. MMM17 was the largest BP screening campaign undertaken in Bangladesh. This study suggests that opportunistic screening can identify significant numbers of people with raised BP. A periodic public health programme at a national level needs to be initiated to increase hypertension detection and control rate and thus for the prevention of cardiovascular diseases

    Vulnerability of low-arsenic aquifers to municipal pumping in Bangladesh

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    Sandy aquifers deposited >12,000 years ago, some as shallow as 30 m, have provided a reliable supply of low-arsenic (As) drinking water in rural Bangladesh. This study concerns the potential risk of contaminating these aquifers in areas surrounding the city of Dhaka where hydraulic heads in aquifers >150 m deep have dropped by 70 m in a few decades due to municipal pumping. Water levels measured continuously from 2012 to 2014 in 12 deep (>150 m), 3 intermediate (90-150 m) and 6 shallow (<90 m) community wells, 1 shallow private well, and 1 river piezometer show that the resulting drawdown cone extends 15-35 km east of Dhaka. Water levels in 4 low-As community wells within the 62-147 m depth range closest to Dhaka were inaccessible by suction for up to a third of the year. Lateral hydraulic gradients in the deep aquifer system ranged from 1.7 × 10-4 to 3.7 × 10-4 indicating flow towards Dhaka throughout 2012-2014. Vertical recharge on the edge of the drawdown cone was estimated at 0.21 ± 0.06 m/yr. The data suggest that continued municipal pumping in Dhaka could eventually contaminate some relatively shallow community wells

    Beautiful Mirrors at the LHC

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    We explore the "Beautiful Mirrors" model, which aims to explain the measured value of AFBbA^b_{FB}, discrepant at the 2.9σ2.9\sigma level. This scenario introduces vector-like quarks which mix with the bottom, subtly affecting its coupling to the ZZ. The spectrum of the new particles consists of two bottom-like quarks and a charge -4/3 quark, all of which have electroweak interactions with the third generation. We explore the phenomenology and discovery reach for these new particles at the LHC, exploring single mirror quark production modes whose rates are proportional to the same mixing parameters which resolve the AFBbA_{FB}^b anomaly. We find that for mirror quark masses ≲500GeV,a14TeVLHCwith300fb−1\lesssim 500 GeV, a 14 TeV LHC with 300 {\rm fb}^{-1} is required to reasonably establish the scenario and extract the relevant mixing parameters.Comment: version to be published in JHE

    Chiral U(1) flavor models and flavored Higgs doublets: the top FB asymmetry and the Wjj

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    We present U(1) flavor models for leptophobic Z' with flavor dependent couplings to the right-handed up-type quarks in the Standard Model, which can accommodate the recent data on the top forward-backward (FB) asymmetry and the dijet resonance associated with a W boson reported by CDF Collaboration. Such flavor-dependent leptophobic charge assignments generally require extra chiral fermions for anomaly cancellation. Also the chiral nature of U(1)' flavor symmetry calls for new U(1)'-charged Higgs doublets in order for the SM fermions to have realistic renormalizable Yukawa couplings. The stringent constraints from the top FB asymmetry at the Tevatron and the same sign top pair production at the LHC can be evaded due to contributions of the extra Higgs doublets. We also show that the extension could realize cold dark matter candidates.Comment: 40 pages, 10 figures, added 1 figure and extended discussion, accepted for publication in JHE

    Effect of low tidal volume ventilation on lung function and inflammation in mice

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    <p>Abstract</p> <p>Background</p> <p>A large number of studies have investigated the effects of high tidal volume ventilation in mouse models. In contrast data on very short term effects of low tidal volume ventilation are sparse. Therefore we investigated the functional and structural effects of low tidal volume ventilation in mice.</p> <p>Methods</p> <p>38 Male C57/Bl6 mice were ventilated with different tidal volumes (Vt 5, 7, and 10 ml/kg) without or with application of PEEP (2 cm H<sub>2</sub>O). Four spontaneously breathing animals served as controls. Oxygen saturation and pulse rate were monitored. Lung function was measured every 5 min for at least 30 min. Afterwards lungs were removed and histological sections were stained for measurement of infiltration with polymorphonuclear leukocytes (PMN). Moreover, mRNA expression of macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)α in the lungs was quantified using real time PCR.</p> <p>Results</p> <p>Oxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05). Pulse rate dropped in all groups without PEEP during mechanical ventilation. In contrast, in the groups with PEEP pulse rate increased over time. These effects were not statistically significant (P > 0.05). Tissue damping (G) and tissue elastance (H) were significantly increased in all groups after 30 min of ventilation (P < 0.05). Only the group with a Vt of 10 ml/kg and PEEP did not show a significant increase in H (P > 0.05). Mechanical ventilation significantly increased infiltration of the lungs with PMN (P < 0.05). Expression of MIP-2 was significantly induced by mechanical ventilation in all groups (P < 0.05). MIP-2 mRNA expression was lowest in the group with a Vt of 10 ml/kg + PEEP.</p> <p>Conclusions</p> <p>Our data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally. Formation of atelectasis and inadequate oxygenation with very low tidal volumes may be important factors. Application of PEEP attenuated inflammation.</p

    Talking Less during Social Interactions Predicts Enjoyment: A Mobile Sensing Pilot Study

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    Can we predict which conversations are enjoyable without hearing the words that are spoken? A total of 36 participants used a mobile app, My Social Ties, which collected data about 473 conversations that the participants engaged in as they went about their daily lives. We tested whether conversational properties (conversation length, rate of turn taking, proportion of speaking time) and acoustical properties (volume, pitch) could predict enjoyment of a conversation. Surprisingly, people enjoyed their conversations more when they spoke a smaller proportion of the time. This pilot study demonstrates how conversational properties of social interactions can predict psychologically meaningful outcomes, such as how much a person enjoys the conversation. It also illustrates how mobile phones can provide a window into everyday social experiences and well-being

    Early star-forming galaxies and the reionization of the Universe

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    Star forming galaxies represent a valuable tracer of cosmic history. Recent observational progress with Hubble Space Telescope has led to the discovery and study of the earliest-known galaxies corresponding to a period when the Universe was only ~800 million years old. Intense ultraviolet radiation from these early galaxies probably induced a major event in cosmic history: the reionization of intergalactic hydrogen. New techniques are being developed to understand the properties of these most distant galaxies and determine their influence on the evolution of the universe.Comment: Review article appearing in Nature. This posting reflects a submitted version of the review formatted by the authors, in accordance with Nature publication policies. For the official, published version of the review, please see http://www.nature.com/nature/archive/index.htm
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