30793 research outputs found
Sort by
The water weakening effect on the progressive slope failure under excavation and rainfall conditions
Get PDFData availability:
The data underpinning this publication can be accessed from Brunel University London's data repository, Brunelfigshare here under a CCBY licence: https://doi.org/10.17633/rd.brunel.26131048 .The water weakening effect refers to the gradual deterioration of soil mechanical properties under long-term saturation. This paper analyzed the impact of water weakening on slope stability under alternating excavation and rainfall. The field investigation speculated shale hydration as the cause of overall slope instability. The mechanical parameters of hydrated shale were determined by the parameter inversion and empirical estimation methods. The simulations were used to restore the process of parameter weakening and slope failure, and confirmed the fact that hydration causes landslide. Furthermore, the failure mechanism of slope and support structure under hydration were investigated. The results show that the mechanical parameters of the slope decreased linearly, whereas the plastic strain–time and total displacement-maximum shear stress curves of the hydrated shale exhibited three stages: slow initial growth, rapid growth in the middle term, and rapid increase in the later period; the rate of slope deformation and the factor of safety reduction also gradually increase over time; under middle stage of hydration, the middle to rear of shale were extruded, while the front first underwent tensile shear deformation, forming a plastic zone of at rear and front excavated slope; In the late stage, hydrated shale quickly reaches its yield limit (maximum shear stress of 270 kPa), the middle and rear shale is damaged and compresses the front, causing it to transform from tensile shear to compressive shear failure. The plastic zone in the rear extends forward and connects with the front ones, forming an overall landslide. Besides, preventing deep landslides caused by hydration through waterproofing, drainage, protection, and support for excavated slopes has proven difficult. Therefore, it is necessary to redesign treatment schemes based on the characteristics of stress, strain, and seepage.UK Research and Innovation (UKRI) (Grant No. EP/Y02754X/1) and the UK Engineering and Physical Sciences Research Council (EPSRC) New Investigator Award (Grant No. EP/V028723/1)
The role of alpha oscillations in free‐ and goal‐directed semantic associations
No full textData availability statement: The data underpinning this publication are available at https://osf.io/gra42 under a CCBY licence https://doi.org/10.17605/OSF.IO/GRA42.Supporting Information is available online at: https://onlinelibrary.wiley.com/doi/10.1002/hbm.26770#support-information-section .Alpha oscillations are known to play a central role in several higher‐order cognitive functions, especially selective attention, working memory, semantic memory, and creative thinking. Nonetheless, we still know very little about the role of alpha in the generation of more remote semantic associations, which is key to creative and semantic cognition. Furthermore, it remains unclear how these oscillations are shaped by the intention to “be creative,” which is the case in most creativity tasks. We aimed to address these gaps in two experiments. In Experiment 1, we compared alpha oscillatory activity (using a method which distinguishes genuine oscillatory activity from transient events) during the generation of free associations which were more vs. less distant from a given concept. In Experiment 2, we replicated these findings and also compared alpha oscillatory activity when people were generating free associations versus associations with the instruction to be creative (i.e. goal‐directed). We found that alpha was consistently higher during the generation of more distant semantic associations, in both experiments. This effect was widespread, involving areas in both left and right hemispheres. Importantly, the instruction to be creative seems to increase alpha phase synchronisation from left to right temporal brain areas, suggesting that intention to be creative changed the flux of information in the brain, likely reflecting an increase in top‐down control of semantic search processes. We conclude that goal‐directed generation of remote associations relies on top‐down mechanisms compared to when associations are freely generated.Fundação Bial. Grant Number: 138/18
Search for pair production of scalar and vector leptoquarks decaying to muons and bottom quarks in proton-proton collisions at = 13 TeV
No full textA preprint version of the article is available at arXiv:2402.08668v2 [hep-ex], https://arxiv.org/abs/2402.08668v2 . Comments: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-21-019 . Report number: CMS-EXO-21-019, CERN-EP-2023-301.A search for pair production of scalar and vector leptoquarks (LQs) each decaying to a muon and a bottom quark is performed using proton-proton collision data collected at √ = 13 TeV with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 138 fb^−1. No excess above standard model expectation is observed. Scalar (vector) LQs with masses less than 1810 (2120) GeV are excluded at 95% confidence level, assuming a 100% branching fraction of the LQ decaying to a muon and a bottom quark. These limits represent the most stringent to date.SCOAP
Assessing Stray DC and AC Current-Induced Corrosion in Steel Fibre-Reinforced Concrete (SFRC) in Railway Tunnelling Construction
Get PDFThis paper discusses the uncertainties surrounding corrosion prompted by stray direct current (DC) and alternating current (AC) interferences. The influence of railway stray DC interference was simulated through cyclic potentiodynamic (CP) polarization in a simulated concrete pore solution. Steel fibres exhibit excellent resistance to stray DC perturbations up to 1.0 V (vs. OCP or Open Circuit Potential) in the absence of chloride. However, when the electrolyte contains 0.6 mol/L chloride, a reduced DC perturbation of 0.4 V (vs. OCP) was sufficient to initiate pitting corrosion, indicating decreased corrosion resistance. The stray AC interference was simulated by applying an AC perturbation test to the embedded steel fibres which were polarized in simulated concrete pore solution as well. This approach allows for the effect of steel fibre orientations under stray AC interferences to be assessed. Following the AC interference test, the Tafel polarisation test shows a stochastic corrosion pattern in the embedded steel fibres. Notably, there is a significant reduction in the corrosion potential (Ecorr) and a corresponding increase in the corrosion current density (icorr) observed in one of the fibres. Ongoing research is being conducted to explore the stochastic corrosion phenomena identified in this research. Boundary element modelling (BEM) results show that the maximum voltage drops between steel fibres arranged in various configurations closely correspond to experimental measurements. The computer simulation approach applied in this study has the potential to further advance the development of more valuable predictive tools in forecasting the corrosion behaviours of reinforced concrete exposed to stray currents under complex built environments
Crack and failure behaviors of sandstone subjected to dynamic loads visualized by micro-computed tomography
Get PDFMicroscopic dynamic failure behaviors of rocks are significant to rock engineering, which is still insufficiently understood. This study combines split Hopkinson pressure bar (SHPB) and micro-CT (computed tomography) to explore the microscopic failure characteristics of sandstone under impact loading. SHPB is responsible for the dynamic test, and micro-CT is responsible for pre- and post-test inspections. The results show that the pores and defect influence the dynamic strength but do not alter the overall trend of increased strength with a higher impact level. The dynamical crack development is then analyzed. Three types of cracks (i.e. I-, Y-, and H-type) are identified to describe the crack development. When rock is simply fractured, only I-type crack exists due to tensile failure, and it grows irregularly. As the strain rate increases, I-type crack is transformed into Y- and H-type crack due to shear failure. Crack coalesces at that moment, and the complexity increases along the impact direction. The coalescence occurs preferentially in the area with more pores, and around a third of pores are involved, where the maximum contribution area is in the middle of sample. Microcracks are formed inside the rock blocks, and rock grains and fragments fill in the cracks. The dynamic crack development is accompanied by microcracks, while rock grains and fragments result from the development of these microcracks. In addition, the influence of a semi-penetrating defect perpendicular to the impact direction is investigated. The defect can impede stress transfer and concentrate energy consumption. The findings are expected to enhance understanding of rock dynamics and support rock engineering development.Research Center for Industries of the Future (RCIF), Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province (No. ZJRMG-2022-03); Key Research and Development Program of Guangxi Province (No. Guike AB22080035)
Fostering a Patient-led Culture of Care Through Data Physicalization: A Design Approach to Create Awareness and Promote Data Collection on Antimicrobial Resistance
Get PDFThe paradigm shift in healthcare delivery models is leading to individuals assuming greater responsibilities and control, as the agency is moving from doctor-centric to patient-centric. To foster a patient-led culture of care, health and data literacy are essential, especially in the context of global challenges, where citizen awareness is fundamental to play actively in co-creating knowledge. This paper outlines a methodological approach and the outcomes of a design research project focused on promoting engagement and literacy to facilitate citizen and patient participation in addressing the antimicrobial resistance threat. The approach is tested in the format of an experimental workshop, inspired by the procedure of the antibiogram. Data physicalization modalities are considered to promote literacy in healthcare and involve citizens in data collection practices to explain the scientific phenomenon of AMR, engage non-experts in understanding antibiotic functionalities and share personal information related to consumption behaviours.MAKEAWARE! is an initiative organised within the flagship project SPEARHEAD, ‘Swiss Pandemic & AMR — Health Economy Awareness Detect’ (SPEARHEAD) and supported by the Swiss Innovation Agency — Innosuisse
Asymmetric heavy-tailed robust loss function for regression, regularisation and fast computation
Get PDFThis thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonRobust inference for outliers to statistics and adversarial samples in deep learning is not
only 'a new tune of an old song', yet also the current hot research topic in both statistics
and artificial intelligence. Asymmetric distributions, including heavy-tailed distributions in
regression models and data analysis have been challenging and are required to take into
account the robustness of methods. Bayesian inference or Bayesian analysis, as one of
the most popular statistics methods, has been widely used in all research elds, including
science, social science and engineering recently. Many regression models face challenging
issues in high-dimensional and computational problems, which has attracted substantial research
in the literature recent years. Therefore, this thesis aims to develop novel Bayesian
methods in parametric statistical inference to address these issues via three attempts. The
rst attempt is to employ Bayesian variable selection with quantile-dependent prior for
the fractional polynomial (FP) model, with a medical application in the analysis of blood
pressure (BP) amongst United States adults. Whilst the FPs act as a concise and accurate
formula for examining smooth relationships between BP measures and risk factors of
cardiovascular disease, conditional quantile functions with FPs provide comprehensive relationships,
including median and extremely high BP measures. The second attempt is to
propose a new asymmetric Huberised loss function taking account of robustness, asymmetry
and heavy tails. This motivates the development of robust Bayesian regularisation for
a high-dimensional setting. The former has its corresponding probability distribution with
the normal scale-mixture property. This leads to a by-product of the research, that is, a
new Bayesian Huberised regularised quantile regression, which is derived by adopting the
Markov chain Monte Carlo (MCMC) method. Finally, the third attempt is to revisit the
work of the previous attempt addressing the computational issue. The MCMC method is
a popular technique for full Bayesian probabilistic models, however, it faces the high computational
cost when the amount of data increases. Alternative to the MCMC method,
variational inference is the approximate-based technique to tackle the computational issue,
and is utilised to propose variational Bayesian Huberised Lasso quantile regression and
variational Bayesian Huberised adaptive Lasso quantile regression for high-dimensional and
computational problems.Engineering and Physical Science Research Council (EPSRC) (DTP PhD studentship grant no. 2295266)
All grown-up; 18 years of LHC@home
Get PDFStatement of Peer review: https://www.epj-conferences.org/articles/epjconf/pdf/2024/05/epjconf_CHEP2023_Statement.pdf .LHC@home was launched as a BOINC project in 2004 as an outreach project for CERN’s 50 years anniversary. Initially focused on the accelerator physics simulation code SixTrack, the project was expanded in 2011 to run other physics simulation codes on Linux thanks to virtualisation. Later on the experiment and theory applications running on the LHC@home platform have evolved to use containers and take advantage of the CVMFS file system as well as content delivery networks. Furthermore, a substantial part of the contributed computing capacity nowadays is provided as opportunistic back-fill from data centers with spare capacity, in addition to enthusiastic volunteers. The paper will address the challenges with this distributed computing model, new applications to exploit GPUs and the future outlook for volunteer computing
5-aza-2′-deoxycytidine induces telomere dysfunction in breast cancer cells
Get PDFSupplementary material is available online at: https://www.sciencedirect.com/science/article/pii/S0753332224010576?via%3Dihub#sec0140 .Aims:
Azacitidine, a drug that epigenetically modifies DNA, is widely used to treat haematological malignancies. However, at low doses, it demethylates DNA, and as a result, can alter gene expression. In our previous publication, we showed that low doses of azacitidine induce telomere length elongation in breast cancer cells. In this study, we aim to identify the mechanisms which lead to telomere length increases.
Methods:
Breast cancer cell lines representing different molecular sub-types were exposed to 5-aza-2′-deoxycytidine (5-aza) in 2 and 3D cultures, followed by DNA, RNA, and protein extractions. Samples were then analysed for telomere length, DNA damage, telomerase, and ALT activity.
Results:
We show that treatment of the cell lines with 5-aza for 72 h induced DNA damage at the telomeres and increased ALT activity 3-fold. We also identified a gene, POLD3, which may be involved in the ALT activity seen after treatment.
Conclusion:
Our results indicate that while 5-aza is a useful drug for treating haematological cancers, surviving cancer cells that have been exposed to lower doses of the drug may activate mechanisms such as ALT. This could lead to cancer cell survival and possible resistance to 5-aza clinically.This work was partly funded by a BRIEF award (11683101) from Brunel University
MedT5SQL: a transformers-based large language model for text-to-SQL conversion in the healthcare domain
Get PDFData availability statement: Publicly available datasets were analyzed in this study. This data can be found at: https://github.com/wangpinggl/TREQS/tree/master/mimicsql_data/mimicsql_natural_v2; https://huggingface.co/datasets/wikisql .Supplementary material: The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fdata.2024.1371680/full#supplementary-material .Introduction: In response to the increasing prevalence of electronic medical records (EMRs) stored in databases, healthcare staff are encountering difficulties retrieving these records due to their limited technical expertise in database operations. As these records are crucial for delivering appropriate medical care, there is a need for an accessible method for healthcare staff to access EMRs.
Methods: To address this, natural language processing (NLP) for Text-to-SQL has emerged as a solution, enabling non-technical users to generate SQL queries using natural language text. This research assesses existing work on Text-to-SQL conversion and proposes the MedT5SQL model specifically designed for EMR retrieval. The proposed model utilizes the Text-to-Text Transfer Transformer (T5) model, a Large Language Model (LLM) commonly used in various text-based NLP tasks. The model is fine-tuned on the MIMICSQL dataset, the first Text-to-SQL dataset for the healthcare domain. Performance evaluation involves benchmarking the MedT5SQL model on two optimizers, varying numbers of training epochs, and using two datasets, MIMICSQL and WikiSQL.
Results: For MIMICSQL dataset, the model demonstrates considerable effectiveness in generating question-SQL pairs achieving accuracy of 80.63%, 98.937%, and 90% for exact match accuracy matrix, approximate string-matching, and manual evaluation, respectively. When testing the performance of the model on WikiSQL dataset, the model demonstrates efficiency in generating SQL queries, with an accuracy of 44.2% on WikiSQL and 94.26% for approximate string-matching.
Discussion: Results indicate improved performance with increased training epochs. This work highlights the potential of fine-tuned T5 model to convert medical-related questions written in natural language to Structured Query Language (SQL) in healthcare domain, providing a foundation for future research in this area.The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇