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Efficient data-driven machine learning models for scour depth predictions at sloping sea defences
Get PDFSeawalls are critical defence infrastructures in coastal zones that protect hinterland areas from storm surges, wave overtopping and soil erosion hazards. Scouring at the toe of sea defences, caused by wave-induced accretion and erosion of bed material imposes a significant threat to the structural integrity of coastal infrastructures. Accurate prediction of scour depths is essential for appropriate and efficient design and maintenance of coastal structures, which serve to mitigate risks of structural failure through toe scouring. However, limited guidance and predictive tools are available for estimating toe scouring at sloping structures. In recent years, Artificial Intelligence and Machine Learning (ML) algorithms have gained interest, and although they underpin robust predictive models for many coastal engineering applications, such models have yet to be applied to scour prediction. Here we develop and present ML-based models for predicting toe scour depths at sloping seawall. Four ML algorithms, namely, Random Forest (RF), Gradient Boosted Decision Trees (GBDT), Artificial Neural Networks (ANNs), and Support Vector Machine Regression (SVMR) are utilised. Comprehensive physical modelling measurement data is utilised to develop and validate the predictive models. A Novel framework for feature selection, feature importance, and hyperparameter tuning algorithms are adopted for pre- and post-processing steps of ML-based models. In-depth statistical analyses are proposed to evaluate the predictive performance of the proposed models. The results indicate a minimum of 80% prediction accuracy across all the algorithms tested in this study and overall, the SVMR produced the most accurate predictions with a Coefficient of Determination (r2) of 0.74 and a Mean Absolute Error (MAE) value of 0.17. The SVMR algorithm also offered most computationally efficient performance among the algorithms tested. The methodological framework proposed in this study can be applied to scouring datasets for rapid assessment of scour at coastal defence structures, facilitating model-informed decision-making
Sibling and peer bullying victimization in adolescence : masculinity, femininity, and the moderating role of sex and popularity
Get PDFIntroduction: We investigated whether gender‐typed traits (masculinity and femininity) contemporaneously predicted self‐reported peer victimization, peer‐reported peer victimization, and sibling victimization. We also tested the moderating role of sex and popularity. Methods: A sample of 2782 British pupils aged 11–16 from Central England, UK was screened for bullying involvement and popularity using self‐report and peer nominations, and a subsample of 704 (52.7% girls) completed a measure of gender‐typed traits (masculinity and femininity). Results: Hierarchical multiple regression analyses revealed that low levels of masculine traits were associated with greater risk of self‐reported peer victimization, there were no associations with peer‐reported peer victimization, and low levels of feminine traits were associated with greater risk of self‐reported sibling victimization. The effects were not moderated by sex, while popularity decreased the risk of self‐ and peer‐reported peer victimization. Conclusions: Bullying prevention interventions could benefit from including the positive facets of feminine and masculine traits
Queering Jewish studies
No full textThis forum brings together eight scholars of various disciplines who take stock of queer perspectives on Jewish Studies, introduce new lines of research, and show the many ways in which queering Jewish Studies energizes the field. The authors also discuss the particular promise of Jewish trans studies as well as the nexus of queers and Jews in the age of rising populism. Overall, the forum serves as a primer for those interested in how to teach or do queer Jewish Studies
Cadaveric biomechanical and laboratory research can be quantitatively scored for quality with the Biomechanics Objective Basic science Quality Assessment Tool : The BOBQAT score
No full textThe purpose of this study was to develop a quality appraisal tool for the assessment of cadaveric biomechanical laboratory and other basic science biomechanical studies. For item identification/development, a systematic review of the literature was first performed. The content validity index (CVI) was used to either include or exclude items. The content validity ratio (CVR) was used to determine content validity. Weighting was performed by each panel member; the final weight was either up- or downgraded to the closest of 5 or 10%. Face validity was scored on a Likert scale ranked from 1-7. Test-retest reliability was determined using the Fleiss kappa coefficient. Internal consistency was assessed with Cronbach's alpha. Concurrent criterion validity was assessed against the QUACS scale. The final BOBQAT score included 15 items and was shown to be valid, reliable and consistent. Five items had a CVI of 1.0; ten items had a CVI of 0.875. For weighting, five items received a weight of 10% and ten items a weight of 5%. CVR was 1.0 for six items and 0.75 for nine items. For face validity, all items achieved a score above 5. For test-retest reliability, almost perfect test-retest reliability was observed for ten items, substantial agreement for four items and moderate agreement for one item. For internal consistency, Cronbach's alpha was calculated to be 0.71. For concurrent criterion validity, Pearson's product-moment correlation was 0.56 (95% CI 0.38-0.70, p=0.0001). Cadaveric biomechanical and laboratory research can be quantitatively scored for quality based on the inclusion of a clear and answerable purpose, demographics, specimen condition, appropriate bone density, reproducible technique, appropriate outcome measures, appropriate loading conditions, appropriate load magnitude, cyclic loading, sample size calculation, proper statistical analysis, results consistent with methods, limitations considered, conclusions based on results, and disclosure of funding and potential conflicts
The role of drag and gravity on dust concentration in a gravitationally unstable disc
Get PDFWe carry out three dimensional smoothed particle hydrodynamics simulations to study the role of gravitational and drag forces on the concentration of large dust grains (St > 1) in the spiral arms of gravitationally unstable protoplanetary discs, and the resulting implications for planet formation. We find that both drag and gravity play an important role in the evolution of large dust grains. If we include both, grains that would otherwise be partially decoupled will become well coupled and trace the spirals. For the dust grains most influenced by drag (with Stokes numbers near unity), the dust disc quickly becomes gravitationally unstable and rapidly forms clumps with masses between 0.15 − 6M⊕. A large fraction of clumps are below the threshold where runaway gas accretion can occur. However, if dust self-gravity is neglected, the dust is unable to form clumps, despite still becoming trapped in the gas spirals. When large dust grains are unable to feel either gas gravity or drag, the dust is unable to trace the gas spirals. Hence, full physics is needed to properly simulate dust in gravitationally unstable discs. Dust trapping of large grains in spiral arms of discs stable to gas fragmentation could explain planet formation in very young discs by a population of planetesimals formed due to the combined roles of drag and gravity in the earliest stages of a disc’s evolution. Furthermore, it highlights that gravitationally unstable discs are not just important for forming gas giants quickly, it can also rapidly form Earth mass bodies
Soft magnetostrictive patches for guided wave ultrasonics using Wiedemann effect-based MPTs and EMATs
No full textMagnetically soft and malleable magnetostrictive (MS) alloys are highly promising as low-cost solutions for high-efficiency generation of guided waves in industrial applications and a variety of magnetostrictive patch transducers (MPTs) have been described in the literature. This work focuses on understanding the mechanisms and behaviour of soft MPTs used in the Wiedemann effect geometry, generating shear horizontal (SH) guided waves using FeCo alloy patches. MPT operation is explored in relation to patch geometry, size, magnetic field directions and guided wave wavelength. MPTs are compared with electromagnetic acoustic transducers (EMATs) and EMATs are also placed on MS and copper foil patches bonded to large glass plates for some of the measurements. Periodic permanent magnet (PPM) array EMATs operating on MPTs bonded to ferritic steel samples produced significant enhancements in the generated wave amplitude and the detected signal amplitude when compared to directly generating on the steel substrate, which primarily operates through the Lorentz mechanism. This enhanced performance was investigated and was found to be due to the magnetic fringing fields at the magnet edges. Moreover, EMAT lift-off behaviour was significantly improved when an EMAT was placed above a magnetostrictive patch, with 50 mm lift-off between the EMAT and the patch demonstrated for SH wave generation at a 22 mm nominal wavelength at a 170 kHz excitation frequency on a glass plate sample
Cirrhotic hepatocellular carcinoma-based decellularized liver cancer model for local chemoembolization evaluation.
No full textTransarterial chemoembolization (TACE) is a common treatment for unresectable intermediate stage hepatocellular carcinoma (HCC) and involves the combination of chemotherapy agents and embolic materials to target and block the blood supply to the tumor, leading to localized treatment. However, the selection of clinical chemoembolization agents remains limited, and the effectiveness of various agents is still under investigation. Meanwhile, replicating the complex vasculature and extracellular matrix (ECM) circumstances of HCC in in vitro models for evaluating embolic agents proves to be challenging. Herein, we developed a decellularized cancerous liver model with translucent appearance, a complicated hepatic vascular system and tissue-specific ECM for the evaluation of embolic agents. Inkpad oil and microparticles were used to illustrate different systems of vascular structures between healthy and HCC rats' livers. Quantitative analysis with AngioTool revealed significant differences in vessel density and lacunarity between the two groups. Proteomics showed higher secretion of collagens in the HCC rat liver models than in healthy livers. Utilizing this in vitro model, we investigated the impact of tumor-specific vascular structure and ECM composition on chemoembolization performance, the two key factors inaccessible by currently available drug release testing platforms. Our findings revealed that the presence of an aberrant vascular system and the distorted ECM within the model led to drug retention. This preclinical model holds great promise as a valuable tool for evaluating embolic agents and studying their performance in the tumor microenvironment. STATEMENT OF SIGNIFICANCE: Transarterial chemoembolization (TACE), which employs drug-eluting embolic agents to obstruct the tumor-feeding vessels while locally releasing chemotherapeutic drugs into the tumor, has become the first-line treatment of unresectable liver cancer over past two decades. Nevertheless, the advancement of effective drug-eluting embolic agents has been retarded due to the lack of appropriate in vitro models for assessing the local embolization and chemotherapy performances in TACE. Here we developed a cirrhotic hepatocellular carcinoma-based decellularized liver cancer model, which preserves the aberrant vasculatures and tumor-specific extracellular matrix of liver cancer, for TACE evaluation. This model incorporates a blood flow simulation component to assess the dynamics of drug release behaviors of chemoembolic agents within tumor-mimicking conditions, more accurately replicating the in vivo environment for the locoregional assessments as compared to conventional in vitro models. [Abstract copyright: Copyright © 2024 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Robotic trials in arthroplasty surgery
No full textTotal hip and knee arthroplasty (THA, TKA) are largely successful procedures; however, both have variable outcomes, resulting in some patients being dissatisfied with the outcome. Surgeons are turning to technologies such as robotic-assisted surgery in an attempt to improve outcomes. Robust studies are needed to find out if these innovations are really benefitting patients. The Robotic Arthroplasty Clinical and Cost Effectiveness Randomised Controlled Trials (RACER) trials are multicentre, patient-blinded randomized controlled trials. The patients have primary osteoarthritis of the hip or knee. The operation is Mako-assisted THA or TKA and the control groups have operations using conventional instruments. The primary clinical outcome is the Forgotten Joint Score at 12 months, and there is a built-in analysis of cost-effectiveness. Secondary outcomes include early pain, the alignment of the components, and medium- to long-term outcomes. This annotation outlines the need to assess these technologies and discusses the design and challenges when conducting such trials, including surgical workflows, isolating the effect of the operation, blinding, and assessing the learning curve. Finally, the future of robotic surgery is discussed, including the need to contemporaneously introduce and evaluate such technologies. [Abstract copyright: © 2024 The British Editorial Society of Bone & Joint Surgery.
High moments of theta functions and character sums
Get PDFAssuming the Generalised Riemann Hypothesis, we prove a sharp upper bound on moments of shifted Dirichlet L‐functions. We use this to obtain conditional upper bounds on high moments of theta functions. Both of these results strengthen theorems of Munsch, who proved almost sharp upper bounds for these quantities. The main new ingredient of our proof comes from a paper of Harper, who showed the related result ∫ 0 T | ζ ( 1 / 2 + i t ) | 2 k ≪ k T ( log T ) k 2 for all k ⩾ 0 under the Riemann Hypothesis. Finally, we obtain a sharp conditional upper bound on high moments of character sums of arbitrary length
On the feasibility of E2E verifiable online voting – a case study from Durga Puja trial
Get PDFIndia is the largest democracy by population and has one of the largest deployments of e-voting in the world for national elections. However, the e-voting machines used in India are not end-to-end (E2E) verifiable. The inability to verify the tallying integrity of an election by the public leaves the outcome open to disputes. E2E verifiable e-voting systems are commonly regarded as the most promising solution to address this problem, but they had not been implemented or trialed in India. It was unclear whether such systems would be usable and practical to the Indian people. Previous works such as Helios require a set of tallying authorities (TAs) to perform the decryption and tallying operations, but finding and managing TAs can prove difficult. This paper presents a TA-free E2E verifiable online voting system based on the DRE-ip protocol. In collaboration with the local authority of New Town, Kolkata, India, we conducted an online voting trial as part of the 2022 Durga Puja festival celebration, during which residents of New Town were invited to use mobile phones to vote for their favorite pujas (festival decorations) in an E2E verifiable manner. 543 participants attended the Durga Puja trial and 95 of them provided feedback by filling in an anonymous survey after voting. Based on the voter feedback, participants generally found the system easy to use. This was the first time that an E2E online voting system had been built and tested in India, suggesting its feasibility for non-statutory voting scenarios