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Some rock joints exhibit significant brittleness, characterized by a sharp decrease in shear stress upon reaching the peak strength. However, existing models often fail to accurately represent this behavior and are encumbered by numerous parameters lacking clear mechanical significance. This study presents a new statistical damage constitutive model rooted in both damage mechanics and statistics, containing only three model parameters. The proposed model encompasses all stages of joint shearing, including the compaction stage, linear stage, plastic yielding stage, drop stage, strain softening stage, and residual strength stage. To derive the analytical expression of the constitutive model, three boundary conditions are introduced. Experimental data from both natural and artificial rock joints is utilized to validate the model, resulting in average absolute relative errors ranging from 3% to 8%. Moreover, a comparative analysis with established models illustrates that the proposed model captures stress drop and post-peak strain softening more effectively, with model parameters possessing clearer mechanical interpretations. Furthermore, parameter analysis is conducted to investigate the impacts of model parameters on the curves and unveil the relationship between these parameters and the mechanical properties of rock joints. Importantly, the proposed model is straightforward in form, and all model parameters can be obtained from direct shear tests, thus facilitating the utilization in numerical simulations.

Abstract Discrete Element Method (DEM) has been successfully utilized to model rock behavior based on particle flow code (PFC), which is extensively employed in solving various problems related to rock engineering and geomechanics. Therefore, a convenient method for selecting appropriate microparameters of PFC for model generation is necessary. The present study aims to develop a novel approach that calculates proper micro-strength parameters for the contact bond model (CBM). Firstly, based on Plackett–Burman (PB) design, qualitative research is conducted and it is found that the main factors that influence the Brazilian tensile strength is microscopic tensile strength. We analyzed the stress conditions of a Brazilian disc’s vertical diameter using both continuum models and DEM. From this analysis, we establish a theoretical relationship between rock tensile strength and micro-strength parameters. Subsequently, a large number of numerical Brazilian tests were conducted to obtain the statistical relationship between the geometric parameters of balls, micro-strength parameters and the Brazilian tension strength. The results of the numerical simulation were then used to refine the theoretical equation mentioned above, resulting in a modified equation for rock tensile strength and micro-strength parameters. Finally, after verification, we confirm the feasibility of the method in this paper.

To investigate the dynamic damage evolution characteristics of bank slopes with serrated structural planes, the shaking table model test and the numerical simulation were utilized. The main findings indicate that under continuous seismic loads, the deformation of the bank slope increased, particularly around the hydro-fluctuation belt, accompanying by the pore water pressure rising. The soil pressure increased and then decreased showed dynamic variation characteristics. As the undulation angle of the serrated structural planes increased (30°, 45°, and 60°), the failure modes were climbing, climbing-gnawing, and gnawing respectively. The first-order natural frequency was used to calculate the damage degree (Dd) of the bank slope. During microseisms and small earthquakes, it was discovered that the evolution of Dd followed the “S” shape, which was fitted by a logic function. Additionally, the quadratic function was used to fit the Dd during moderately strong earthquakes. Through the numerical simulation, the variation characteristics of safety factors (Sf) for slopes with serrated structural planes and slopes with straight structural planes were compared. Under continuous seismic loads, the Sf of slopes with straight structural planes reduce stalely, whereas the Sf for slopes with serrated structural planes was greater than the former and the reduction rate was increasing.

The aim of this paper is to first of all determine, and later to explain the cause-and-effect relationship between culture and strategic leadership, as well as their influence on the results of international development projects (ID). In the first segment of the paper, we will explain the concept of international development projects and how they differ from profit projects. Then we will explain the differences between leaders and managers, in order to define as precisely as possible the functions and tasks that leaders have in the implementation of projects. We will also explain why it is important for the success of projects for leaders to understand different cultures. By considering at all these factors, with the help of the developed model, presented in this paper, we will show how culture affects the choice of leadership strategy and how it affects the critical success factors (KFU) as well as the outcome of international development projects.

In terms of the degradation of mechanical parameters of rock mass in the hydrofluctuation belt of a reservoir bank slope arising from rainfall and the reservoir level fluctuation, the moderately weathered sandstone in a side slope of the Three Gorges Reservoir Region is selected as a research object to carry out “drying-saturation-drying” tests for disks with two thicknesses (h=25 mm, h=50 mm) in different cycles; a spiral CT machine, an ultrasonic velocity meter, and a light Schmidt hammer are utilzed to conduct nondestructive testing on dry-wet cycles; through the Brazilian splitting test, the uniaxial tensile strength of “dry” and “saturated” sandstones under different dry-wet cycles is obtained. The research shows that, with the increase of the dry-wet circles (n), the longitudinal wave velocity and the rebound strength of sandstones are linearly decreased with n; the uniaxial tensile strength of sandstones and the mean CT number of cross sections are logarithmically decreased with n; the fitting equation of macro/micromechanical parameters and dry-wet cycles (n) of sandstones is raised, which is provided as a reference basis for the weathering process of sandstones under dry-wet cycles.

Background: Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. Obesity exacerbates the reproductive complications of PCOS; however, the management of obesity in women with PCOS remains a large unmet clinical need. Observational studies have indicated that bariatric surgery could improve the rates of ovulatory cycles and prospects of fertility; however, the efficacy of surgery on ovulation rates has not yet been compared with behavioural modifications and medical therapy in a randomised trial. The aim of this study was to compare the safety and efficacy of bariatric surgery versus medical care on ovulation rates in women with PCOS, obesity, and oligomenorrhoea or amenorrhoea., Methods: In this multicentre, open-label, randomised controlled trial, 80 women older than 18 years, with a diagnosis of PCOS based on the 2018 international evidence-based guidelines for assessing and managing PCOS, and a BMI of 35 kg/m 2 or higher, were recruited from two specialist obesity management centres and via social media. Participants were randomly assigned at a 1:1 ratio to either vertical sleeve gastrectomy or behavioural interventions and medical therapy using a computer-generated random sequence (PLAN procedure in SAS) by an independent researcher not involved with any other aspect of the clinical trial. The median age of the entire cohort was 31 years and 79% of participants were White. The primary outcome was the number of biochemically confirmed ovulatory events over 52 weeks, and was assessed using weekly serum progesterone measurements. The primary endpoint included the intention-to-treat population and safety analyses were per-protocol population. This study is registered with the ISRCTN registry (ISRCTN16668711)., Findings: Participants were recruited from Feb 20, 2020 to Feb 1, 2021. 40 participants were assigned to each group and there were seven dropouts in the medical group and ten dropouts in the surgical group. The median number of ovulations was 6 (IQR 3·5-10·0) in the surgical group and 2 (0·0-4·0) in the medical group. Women in the surgical group had 2.5 times more spontaneous ovulations compared with the medical group (incidence rate ratio 2·5 [95% CI 1·5-4·2], p<0·0007). There were more complications in the surgical group than the medical group, although without long-term sequelae. There were 24 (66·7%) adverse events in the surgical group and 12 (30·0%) in the medical group. There were no treatment-related deaths., Interpretation: Bariatric surgery was more effective than medical care for the induction of spontaneous ovulation in women with PCOS, obesity, and oligomenorrhoea or amenorrhoea. Bariatric surgery could, therefore, enhance the prospects of spontaneous fertility in this group of women., Funding: The Jon Moulton Charity Trust., Competing Interests: Declaration of interests ADM has received research funding from the Medical Research Council (MRC), National Institute for Health and Care Research (NIHR), Jon Moulton Charitable Foundation, Anabio, Fractyl, Boehringer Ingelheim, Gila, Randox, and Novo Nordisk. ADM has received honoraria for lectures and presentations from Novo Nordisk, AstraZeneca, Currax Pharmaceuticals, Boehringer Ingelheim, Screen Health, GI Dynamics, Algorithm, Eli Lilly, Ethicon, and Medtronic. ADM and CWlR are shareholders in the Beyond BMI clinic, which provides clinical obesity care. SA was supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project (PNURSP2024R530), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia. CWlR reported grants from the Irish Research Council, Science Foundation Ireland, Anabio, and the Health Research Board. CWlR has received honoraria for lectures and presentations from Novo Nordisk, Herbalife, Eli Lilly, Johnson & Johnson, Rhythm Pharmaceuticals, Currax Pharmaceuticals, and Boehringer Ingelheim. CWlR serves on advisory boards of Novo Nordisk, Herbalife, GI Dynamics, Eli Lilly, Johnson & Johnson, Altimmune, Irish Life Health, and Boehringer Ingelheim. CWlR plays a leadership role in the Irish Society for Nutrition and Metabolism. CWlR was the Chief Medical Officer and Director of the Medical Device Division of Keyron in 2021—both of these were unremunerated positions. CWlR was a previous investor in Keyron, which developed endoscopically implantable medical devices that mimic the surgical procedures of sleeve gastrectomy and gastric bypass. CWlR does not have any contracts with other companies to put their products into clinical practice. CWlR continues to provide scientific advice to Keyron for no remuneration. AA was supported by the NIHR Clinician Scientist Award and MRC project grant. AA has received consulting fees from Myovant Sciences and honoraria for a lecture from Merck. AA serves on the public engagement committee of the Society for Endocrinology. FS has received a grant from the Deutsche Forschungsgemeinschaft (2027/5–1). BL, AD, and PT received a grant from the Jon Moulton Charitable Foundation. GKD has received research grants from the NIHR, Novo Nordisk, and Diabetes Digital Media, as well as payment or honoraria for lectures and presentations from Novo Nordisk, Rhythm Pharmaceuticals, Eli Lilly, Ethicon, and Medtronic. GKD is a co-founder and shareholder in the Heracles Project clinic, which provides clinical care for men's health. GKD plays a leadership role in The Association for the Study of Obesity and is a member of the Society for Endocrinology–British Endocrine Society. RM has received a grant from the Waterloo Foundation, as well as payment and support from Roche Diagnostics and the Androgen Excess and Polycystic Ovary Syndrome Society. HR has received a grant from the Jon Moulton Charitable Foundation, as well as payment or honoraria from Novo Nordisk and support from Ipsen. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Unlike various countries and organisations, including the World Health Organisation and the European Parliament, the United Kingdom does not formally recognise obesity as a disease. This report presents the discussion on the potential impact of defining obesity as a disease on the patient, the healthcare system, the economy, and the wider society. A group of speakers from a wide range of disciplines came together to debate the topic bringing their knowledge and expertise from backgrounds in medicine, psychology, economics, and politics as well as the experience of people living with obesity. The aim of their debate was not to decide whether obesity should be classified as a disease but rather to explore what the implications of doing so would be, what the gaps in the available data are, as well as to provide up-to-date information on the topic from experts in the field. There were four topics where speakers presented their viewpoints, each one including a question-and-answer section for debate. The first one focused on the impact that the recognition of obesity could have on people living with obesity regarding the change in their behaviour, either positive and empowering or more stigmatising. During the second one, the impact of defining obesity as a disease on the National Health Service and the wider economy was discussed. The primary outcome was the need for more robust data as the one available does not represent the actual cost of obesity. The third topic was related to the policy implications regarding treatment provision, focusing on the public's power to influence policy. Finally, the last issue discussed, included the implications of public health actions, highlighting the importance of the government's actions and private stakeholders. The speakers agreed that no matter where they stand on this debate, the goal is common: to provide a healthcare system that supports and protects the patients, strategies that protect the economy and broader society, and policies that reduce stigma and promote health equity. Many questions are left to be answered regarding how these goals can be achieved. However, this discussion has set a good foundation providing evidence that can be used by the public, clinicians, and policymakers to make that happen., Competing Interests: All authors declare no competing interests relevant to this conference report. ADM has received grants or contracts from Fractyl, Novo Nordisk and Randox, and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Novo Nordisk AstraZeneca, Currax and BI. HP has received grant funding paid to institutions, from Public Health England, the Office for Health Improvement and Disparities, and the National Institute for Health Research; honoraria for educational events from Johnson & Johnson; as well as honoraria for educational materials and accompanying presentations – arms length sponsorship and travel expenses for delivering an educational presentation from Novo Nordisk. She has also had unpaid leadership or fiduciary roles as a British Obesity and Metabolic Surgery Society council member, Obesity Empowerment Network professional steering group co-opted member and NICE weight management guidelines committee member. EFr has received research grants from NIHR (NIHR 152858; NIHR204247; NIHR300773; NIHR133099; NIHR203012; NIHR 13/164/51; RP-PG-0618-20008), and UKRI (BB/V004832/1); Royalties from authorship on an OUP Book from Oxford University Press; travel and accommodation support for attending the UK ASO22 conference from the Association for Study of Obesity, and travel support for attending an NIHR Academy training meeting in London as invited speaker from NIHR. She has also had leadership or fiduciary roles as an Elected Board member for the International Health Economics Association and a Member of NIHR Public Health Research funding panel. SB has received a grant paid to his employer, the Institute for Employment Studies IES, from Novo Nordisk to conduct research on obesity stigma in employment. IES retains full editorial control of all research outputs. AB has received researcher led research support and supported attendance of the Obesity Week/BOMSS 2022 from Novo Nordisk, and researcher led research grants from NIHR/BRC, Rosetrees Trust, MRC, BDA, BBSRC and Innovate UKRI. He has also received personal honoraria for presentations/chairing from Novo Nordisk, personal honoraria from Obesity UK and Johnson & Johnson, institutional fees from PHE and stocks from Reset Health Ltd. He has had unpaid leadership or fiduciary roles as Vice Chair Obesity Specialist Group for British Dietetic Association, Committee member OPEN, Scientific Council for British Nutrition Foundation, and Strategic Council for All Party Parliamentary Group on Obesity. JL has received grants or contracts, paid to institutions, from the National Institute of Health Research and personal consulting fees, support for attending meetings and/or travel, as well as participation on a Data Safety Monitoring Board or Advisory Board from Novo Nordisk. She is also a Current employee of AstraZeneca but was not at the time of this work and AstraZeneca had no role in this work. NI has received a grant from NIHR, payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Obesity Empowerment Network, National Obesity Audit, Novo Nordisk and Johnson & Johnson, as well as support for attending meetings and/or travel from SQOT and BOMSS. She has also had leadership or fiduciary roles for Obesity Empowerment Network and BOMSS. ML has received consulting fees from Novo Nordisk and Nestle and payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Nestle, Oviva, Roche and Novo Nordisk. SW has had travel costs paid by Novo Norisk for attendance at obesity conferences. KC has received payment for Lecture Apollo Endosurgery and speaking fees from Novo Nordisk. GKD has received research grants from Novo Nordisk and DDM, as well as payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Novo Nordisk and J&J/Ethicon & Medtronic. SLB has received direct payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Novo Nordisk and Guys & St Thomas Trust, as well as direct payment for expert testimony from Novo Nordisk. JM has an unpaid leadership or fiduciary role in the Association for the Study of Obesity as a Trustee. RLB has received personal payments for consulting fees from Novo Nordisk, Pfizer, Eli Lilly, ViiV, Gila and Therapeutics Ltd; personal payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from International Medical Press, Novo Nordisk, ViiV, Eli Lilly and Medscape; support for attending meetings and/or travel from Novo Nordisk and Eli Lilly, and personal payment for participation on a Data Safety Monitoring Board or Advisory Board from Novo Nordisk, Pfizer, Eli Lilly, ViiV, Gila and Therapeutics Ltd. She also has unpaid leadership or fiduciary roles as Chair of the Royal College of Physicians (RCPs) Advisory Group on Nutrition, Weight and Health, Member of the RCPs Advisory Group on Health Inequalities, Founding member, Trustee and Steering Group Chair for the Obesity Empowerment Network UK, Committee Member for BOMMS, Committee Member for NBSR, Co-opted Trustee ASO, and Co-Chair of NHS England Tier 3 and Tier 4 Clinical Advisory Group., (© 2023 The Authors.)