1,371 research outputs found

    Direct observation of molecular cooperativity near the glass transition

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    We describe direct observations of molecular cooperativity near the glass transition in poly-vinyl-acetate (PVAc), through nanometer-scale probing of dielectric fluctuations. Molecular clusters switched spontaneously between two to four distinct configurations, producing complex random-telegraph-signals (RTS). Analysis of the RTS and their power spectra shows that individual clusters exhibit both transient dynamical heterogeneity and non-exponential kinetics.Comment: 14 pages pdf, need Acrobat Reade

    Hospital discharge data is not accurate enough to monitor the incidence of postpartum hemorrhage.

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    Postpartum hemorrhage remains a leading cause of maternal morbidity and mortality worldwide. Therefore, cumulative incidence of postpartum hemorrhage and severe postpartum hemorrhage are commonly monitored within and compared across maternity hospitals or countries for obstetrical safety improvement. These indicators are usually based on hospital discharge data though their accuracy is seldom assessed. We aimed to measure postpartum hemorrhage and severe postpartum hemorrhage using electronic health records and hospital discharge data separately and compare the detection accuracy of these methods to manual chart review, and to examine the temporal trends in cumulative incidence of these potentially avoidable adverse outcomes. We analyzed routinely collected data of 7904 singleton deliveries from a large Swiss university hospital for a three year period (2014-2016). We identified postpartum hemorrhage and severe postpartum hemorrhage in electronic health records by text mining discharge letters and operative reports and calculating drop in hemoglobin from laboratory tests. Diagnostic and procedure codes were used to identify cases in hospital discharge data. A sample of 334 charts was reviewed manually to provide a reference-standard and evaluate the accuracy of the other detection methods. Sensitivities of detection algorithms based on electronic health records and hospital discharge data were 95.2% (95% CI: 92.6% 97.8%) and 38.2% (33.3% to 43.0%), respectively for postpartum hemorrhage, and 87.5% (85.2% to 89.8%) and 36.2% (26.3% to 46.1%) for severe postpartum hemorrhage. Postpartum hemorrhage cumulative incidence based on electronic health records decreased from 15.6% (13.1% to 18.2%) to 8.5% (6.7% to 10.5%) from the beginning of 2014 to the end of 2016, with an average of 12.5% (11.8% to 13.3%). The cumulative incidence of severe postpartum hemorrhage remained at approximately 4% (3.5% to 4.4%). Hospital discharge data-based algorithms provided significantly underestimated incidences. Hospital discharge data is not accurate enough to assess the incidence of postpartum hemorrhage at hospital or national level. Instead, automated algorithms based on structured and textual data from electronic health records should be considered, as they provide accurate and timely estimates for monitoring and improvement in obstetrical safety. Furthermore, they have the potential to better code for postpartum hemorrhage thus improving hospital reimbursement

    Hierarchic Superposition Revisited

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    Many applications of automated deduction require reasoning in first-order logic modulo background theories, in particular some form of integer arithmetic. A major unsolved research challenge is to design theorem provers that are "reasonably complete" even in the presence of free function symbols ranging into a background theory sort. The hierarchic superposition calculus of Bachmair, Ganzinger, and Waldmann already supports such symbols, but, as we demonstrate, not optimally. This paper aims to rectify the situation by introducing a novel form of clause abstraction, a core component in the hierarchic superposition calculus for transforming clauses into a form needed for internal operation. We argue for the benefits of the resulting calculus and provide two new completeness results: one for the fragment where all background-sorted terms are ground and another one for a special case of linear (integer or rational) arithmetic as a background theory

    Evolutions of the Reference Values Used in Transport CBA National Guidelines of 3 Countries and What they Reveal

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    The paper presents, analyses and compares the evolution of reference values used in national guidelines issued for cost-benefit analysis of transport infrastructure projects, over the last fifty years, in France, UK and Germany

    Structure and dynamics in protic ionic liquids: a combined optical Kerr-effect and dielectric relaxation spectroscopy study

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    The structure and dynamics of ionic liquids (ILs) are unusual due to the strong interactions between the ions and counter ions. These microscopic properties determine the bulk transport properties critical to applications of ILs such as advanced fuel cells. The terahertz dynamics and slower relaxations of simple alkylammonium nitrate protic ionic liquids (PILs) are here studied using femtosecond optical Kerr-effect spectroscopy, dielectric relaxation spectroscopy, and terahertz time-domain spectroscopy. The observed dynamics give insight into more general liquid behaviour while comparison with glass-forming liquids reveals an underlying power-law decay and relaxation rates suggest supramolecular structure and nanoscale segregation

    Postpartum Hemorrhage: Differences in Definition, Data and Incidence

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    Introduction Postpartum hemorrhage (PPH) remains a major cause of morbidity and mortality worldwide. Geo-temporal comparisons of in-hospital PPH incidence remain a challenge due to differences in definition, data quality and the absence of accurate, validated indicators. Objectives and Approach To compare the incidence of PPH using different definitions to assess the need for a validated indicator. Singleton births from 2014-2016 at Lausanne University Hospital, Switzerland, were included. PPH was defined based on 1) clinical diagnosis using International Classification of Diseases (ICD-10-GM) PPH diagnostic codes, 2) volume of blood loss ≥500ml for vaginal births and ≥1000ml for cesareans 3) peripartum Hb change >2g/dl in vaginal births and ≥4g/dl in cesareans and 4) fulfillment of criteria from definition one, two or three. Data were extracted from hospital discharge data and linked with electronic health records. Results There were 2529, 2660 and 2715 singleton births in 2014, 2015 and 2016, respectively, 28.8% were cesareans. Peripartum change in Hb was available for 17% of births. The incidence (95% CI) of PPH in 2014, 2015 and 2016 was, respectively: 1)6.0% (5.1, 7.0), 6.3% (5.4, 7.3) and 7.9% (6.9, 9.0) based on diagnostic codes; 2)7.9% (6.8, 9.0), 7.1% (6.2, 8.2) and 7.2% (6.3, 8.3) based on blood loss volumes; 3)2.4% (1.8, 3.1), 2.7% (2.1, 3.4) and 3.5% (2.9, 4.3) based on change in Hb; 4)11.3% (10.1, 12.6), 10.4% (9.3, 11.6) and 11.0% (9.9, 12.3) based on the combined definition. Differences in PPH incidence by year between definitions one and four, two and four and three and four were all statistically significant (McNemar p-values Conclusion/Implications Incidence varied widely according to definition and data availability, not to mention data quality. Our results highlight the need for a validated PPH indicator to enable monitoring. Future prospects include the validation of a diagnostic code based PPH indicator aided by text mining in electronic health records

    Post-Transcriptional Regulation of Interleukin-6 Gene Expression in Human Keratinocytes by Ultraviolet B Radiation

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    Exposure to increasing doses (290-315 nm) of ultraviolet (UV) B radiation is thought to profoundly affect human health. Studies on the biologic and molecular effects of UVB radiation on human skin are therefore of particular interest. There is experimental and clinical evidence to assume that UVB radiation-induced local and systemic inflammatory reactions might be mediated at least in part by UVB-induced keratinocyte-derived interleukin (IL)-6. Previously, a UVB-induced increase of steady-state levels of IL-6 mRNA was found to be a prerequisite for keratinocyte IL-6 production after UVB irradiation. The present study was aimed at addressing the question of whether in vitro UVB irradiation would increase IL-6 mRNA expression in long-term cultured, normal human keratinocytes via transcriptional or post-transcriptional mechanisms. UVB exposure (0-100 J/m2) of keratinocytes increased low baseline expression levels of lL-6 mRNA in a time- and dose-dependent manner. Using nuclear run-on assays, transcription rates of the II,-6 gene in nuclei isolated from UVB-irradiated cells were found to be essentially identical to those seen in unirradiated cells, indicating that UVB light did not lead to increased transcription of the IL-6 gene. To determine a possible post-transcriptional mechanism in UVB-induced IL-6 mRNA expression, the effects of UVB irradiation on IL-6 mRNA stability were examined. To this end irradiated and unirradiated keratinocytes were treated with actinomycin D and subjected to Northern blot analysis to calculate IL-6 mRNA half-life. As compared with unirradiated cells, IL-6 mRNA stability was increased significantly (three- to four-fold) in UVB-irradiated cells, suggesting that UVB radiation upregulates IL-6 mRNA levels in human keratinocytes by increasing the stability of IL-6 transcripts. This is the first report indicating that UVB radiation at a physiologically relevant dose may affect gene expression in human cells at a post-transcriptional level

    Unbounded violation of tripartite Bell inequalities

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    We prove that there are tripartite quantum states (constructed from random unitaries) that can lead to arbitrarily large violations of Bell inequalities for dichotomic observables. As a consequence these states can withstand an arbitrary amount of white noise before they admit a description within a local hidden variable model. This is in sharp contrast with the bipartite case, where all violations are bounded by Grothendieck's constant. We will discuss the possibility of determining the Hilbert space dimension from the obtained violation and comment on implications for communication complexity theory. Moreover, we show that the violation obtained from generalized GHZ states is always bounded so that, in contrast to many other contexts, GHZ states do in this case not lead to extremal quantum correlations. The results are based on tools from the theories of operator spaces and tensor norms which we exploit to prove the existence of bounded but not completely bounded trilinear forms from commutative C*-algebras.Comment: Substantial changes in the presentation to make the paper more accessible for a non-specialized reade
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