1,657 research outputs found

    Automated Seismic Source Characterisation Using Deep Graph Neural Networks

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    Most seismological analysis methods require knowledge of the geographic location of the stations comprising a seismic network. However, common machine learning tools used in seismology do not account for this spatial information, and so there is an underutilised potential for improving the performance of machine learning models. In this work, we propose a Graph Neural Network (GNN) approach that explicitly incorporates and leverages spatial information for the task of seismic source characterisation (specifically, location and magnitude estimation), based on multi-station waveform recordings. Even using a modestly-sized GNN, we achieve model prediction accuracy that outperforms methods that are agnostic to station locations. Moreover, the proposed method is flexible to the number of seismic stations included in the analysis, and is invariant to the order in which the stations are arranged, which opens up new applications in the automation of seismological tasks and in earthquake early warning systems

    Direct detection of methylation in genomic DNA

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    The identification of methylated sites on bacterial genomic DNA would be a useful tool to study the major roles of DNA methylation in prokaryotes: distinction of self and nonself DNA, direction of post-replicative mismatch repair, control of DNA replication and cell cycle, and regulation of gene expression. Three types of methylated nucleobases are known: N(6)-methyladenine, 5-methylcytosine and N(4)-methylcytosine. The aim of this study was to develop a method to detect all three types of DNA methylation in complete genomic DNA. It was previously shown that N(6)-methyladenine and 5-methylcytosine in plasmid and viral DNA can be detected by intersequence trace comparison of methylated and unmethylated DNA. We extended this method to include N(4)-methylcytosine detection in both in vitro and in vivo methylated DNA. Furthermore, application of intersequence trace comparison was extended to bacterial genomic DNA. Finally, we present evidence that intrasequence comparison suffices to detect methylated sites in genomic DNA. In conclusion, we present a method to detect all three natural types of DNA methylation in bacterial genomic DNA. This provides the possibility to define the complete methylome of any prokaryote

    Vaginal yeast infections in diabetic women

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    Two hundred and three diabetic women (89 with and 114 without genital symptoms) were examined for the presence of yeasts and Trichomonas vaginalis. Yeasts were isolated from the vaginas of 35,5% of patients and were more common in the symptomatic group (48,0%) than the asymptomatic group (25,4%; P < 0,(5). Candida albicans was isolated from 12,8% of all patients and showed a significant association with pruritus vulvae (P < 0,(5). A significant association was also shown between the presence of yeasts in the rectum and in the vagina. C. glabrata (Torulopsis glabrata) was the COmDlonest yeast species isolated (50,0%), with C. albicans the next most frequent (36,1%). T. vaginalis infection was present in 14,3% of all subjects

    A comparison between rate-and-state friction and microphysical models, based on numerical simulations of fault slip

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    Rate-and-state friction (RSF) is commonly used for the characterisation of laboratory friction experiments, such as velocity-step tests. However, the RSF framework provides little physical basis for the extrapolation of these results to the scales and conditions of natural fault systems, and so open questions remain regarding the applicability of the experimentally obtained RSF parameters for predicting seismic cycle transients. As an alternative to classical RSF, microphysics-based models offer means for interpreting laboratory and field observations, but are generally over-simplified with respect to heterogeneous natural systems. In order to bridge the temporal and spatial gap between the laboratory and nature, we have implemented existing microphysical model formulations into an earthquake cycle simulator. Through this numerical framework, we make a direct comparison between simulations exhibiting RSF-controlled fault rheology, and simulations in which the fault rheology is dictated by the microphysical model. Even though the input parameters for the RSF simulation are directly derived from the microphysical model, the microphysics-based simulations produce significantly smaller seismic event sizes than the RSF-based simulation, and suggest a more stable fault slip behaviour. Our results reveal fundamental limitations in using classical rate-and-state friction for the extrapolation of laboratory results. The microphysics-based approach offers a more complete framework in this respect, and may be used for a more detailed study of the seismic cycle in relation to material properties and fault zone pressure-temperature conditions

    Основні етапи та особливості правового регулювання фінансування будівництва залізниць на території України в другій половині ХІХ – на початку ХХ ст.

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    Досліджуються питання розвитку та вдосконалення залізничного транспорту України, який постає у державі як одна з ланок поліпшення соціально-економічного життя суспільства. Розкриваються проблеми нормативно-правового регулювання виникнення залізничного транспорту в Україні.Рассматриваются вопросы развития и усовершенствования железнодорожного транспорта Украины, который является для государства звеном улучшения социально-экономической жизни общества. Раскрываются проблемы нормативно-правового регулирования возникновения железнодорожного транспорта в Украине.The guestions of development and improvement of the Ukrainian railvay transport which is consideret to be as one of the directions of making better social-economic life of society are investigated. The problems of normative\loyal regulating of the appearing of railwaj transport in Ukraine (the second half of the nineteenth century)
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