103 research outputs found

    Benchmarking the P-MLQMC method on a geotechnical engineering problem

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    Problems in civil engineering are often characterized by significant uncertainty in their material parameters. Sampling methods are a straightforward manner to account for this uncertainty, which is typically modeled as a random field. A novel method developed by the authors called p-refined Multilevel Quasi-Monte Carlo (p-MLQMC), achieves a significant computational cost reduction with respect to classic Multilevel Monte Carlo (h-MLMC). p-MLQMC uses a hierarchy of p-refined Finite Element meshes, combined with a deterministic Quasi-Monte Carlo (QMC) sampling rule. A non-negligible part of modeling the stochastics in non-deterministic engineering problems consists in adequately incorporating the uncertainty in the Finite Element model. This is typically done by evaluating the random field at certain carefully chosen evaluation points, and assigning the resulting scalars to the different finite elements. For the h-MLMC method, these evaluation points consist of the centroids of the elements. For the p-MLQMC method, we distinguish two different approaches to select the evaluation points, the Non-Nested Approach (NNA) and the Local Nested Approach(LNA). We investigate how these approaches affect the variance reduction over the levels and the total computational cost. We benchmark the p-ML(Q)MC-LNA, p-ML(Q)MC-NNA and h-MLMC method on a slope stability problem where the uncertainty is located in the soil's cohesion. We show that the p-MLQMC-LNA method outperforms all other considered methods in terms of computational cost

    Cancer burden in adolescents and young adults in Europe

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    Background Cancer epidemiology is unique in adolescents and young adults (AYAs; aged 15-39 years). The European Society for Medical Oncology/European Society for Paediatric Oncology (ESMO/SIOPE) AYA Working Group aims to describe the burden of cancers in AYAs in Europe and across European Union (EU) countries. Patients and methods We used data available on the Global Cancer Observatory. We retrieved crude and age-standardised (World Standard Population) incidence and mortality rates. We reported about AYA cancer burden in Europe and between 28 EU member states. We described incidence and mortality for all cancers and for the 13 cancers most relevant to the AYA population. Results Incidence and mortality varied widely between countries with the highest mortality observed in Eastern EU countries. Cancers of the female breast, thyroid and male testis were the most common cancers across countries followed by melanoma of skin and cancers of the cervix. Variations in cancer incidence rates across different populations may reflect different distribution of risk factors, variations in the implementation or uptake of screening as well as overdiagnosis. AYA cancer mortality disparities may be due to variation in early-stage diagnoses, different public education and awareness of cancer symptoms, different degrees of access or availability of treatment. Conclusions Our results highlight the future health care needs and requirements for AYA-specialised services to ensure a homogeneous treatment across different countries as well as the urgency for preventive initiatives that can mitigate the increasing burden

    The ChatGPT Artificial Intelligence Chatbot: How Well Does It Answer Accounting Assessment Questions?

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    ChatGPT, a language-learning model chatbot, has garnered considerable attention for its ability to respond to users’ questions. Using data from 14 countries and 186 institutions, we compare ChatGPT and student performance for 28,085 questions from accounting assessments and textbook test banks. As of January 2023, ChatGPT provides correct answers for 56.5 percent of questions and partially correct answers for an additional 9.4 percent of questions. When considering point values for questions, students significantly outperform ChatGPT with a 76.7 percent average on assessments compared to 47.5 percent for ChatGPT if no partial credit is awarded and 56.5 percent if partial credit is awarded. Still, ChatGPT performs better than the student average for 15.8 percent of assessments when we include partial credit. We provide evidence of how ChatGPT performs on different question types, accounting topics, class levels, open/closed assessments, and test bank questions. We also discuss implications for accounting education and research

    Care of adolescents and young adults with cancer in Asia: results of an ESMO/SIOPE/SIOP Asia survey

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    Background Adolescents and young adults (AYAs) with cancer require dedicated management encompassing both adult and paediatric cancer services. Following a European survey, the European Society for Medical Oncology, the European Society for Paediatric Oncology and the Asian continental branch of International Society of Paediatric Oncology undertook a similar survey to assess AYA cancer care across Asia. Methods A link to the online survey was sent to healthcare professionals (HCPs) in Asia interested in AYA cancer care. Questions covered the demographics and training of HCPs, their understanding of AYA definition, availability and access to specialised AYA services, the support and advice offered during and after treatment, and factors of treatment non-compliance. Results We received 268 responses from 22 Asian countries. There was a striking variation in the definition of AYA (median lower age 15 years, median higher age 29 years). The majority of the respondents (78%) did not have access to specialised cancer services and 73% were not aware of any research initiatives for AYA. Over two-thirds (69%) had the option to refer their patients for psychological and/or nutritional support and most advised their patients on a healthy lifestyle. Even so, 46% did not ask about smokeless tobacco habits and only half referred smokers to a smoking cessation service. Furthermore, 29% did not promote human papillomavirus vaccination for girls and 17% did not promote hepatitis B virus vaccination for high-risk individuals. In terms of funding, 69% reported governmental insurance coverage, although 65% reported that patients self-paid, at least partially. Almost half (47%) reported treatment non-compliance or abandonment as an issue, attributed to financial and family problems (72%), loss of follow-up (74%) and seeking of alternative treatments (77%). Conclusions Lack of access to and suboptimal delivery of AYA-specialised cancer care services across Asia pose major challenges and require specific interventions

    The Gracilis Myocutaneous Free Flap: A Quantitative Analysis of the Fasciocutaneous Blood Supply and Implications for Autologous Breast Reconstruction

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    BACKGROUND: Mastectomies are one of the most common surgical procedures in women of the developed world. The gracilis myocutaneous flap is favoured by many reconstructive surgeons due to the donor site profile and speed of dissection. The distal component of the longitudinal skin paddle of the gracilis myocutaneous flap is unreliable. This study quantifies the fasciocutaneous vascular territories of the gracilis flap and offers the potential to reconstruct breasts of all sizes. METHODS: Twenty-seven human cadaver dissections were performed and injected using lead oxide into the gracilis vascular pedicles, followed by radiographic studies to identify the muscular and fasciocutaneous perforator patterns. The vascular territories and choke zones were characterized quantitatively using the 'Lymphatic Vessel Analysis Protocol' (LVAP) plug-in for Image J® software. RESULTS: We found a step-wise decrease in the average vessel density from the upper to middle and lower thirds of both the gracilis muscle and the overlying skin paddle with a significantly higher average vessel density in the skin compared to the muscle. The average vessel width was greater in the muscle. Distal to the main pedicle, there were either one (7/27 cases), two (14/27 cases) or three (6/27 cases) minor pedicles. The gracilis angiosome was T-shaped and the maximum cutaneous vascular territory for the main and first minor pedicle was 35 × 19 cm and 34 × 10 cm, respectively. CONCLUSION: Our findings support the concept that small volume breast reconstructions can be performed on suitable patients, based on septocutaneous perforators from the minor pedicle without the need to harvest any muscle, further reducing donor site morbidity. For large reconstructions, if a 'T' or tri-lobed flap with an extended vertical component is needed, it is important to establish if three territories are present. Flap reliability and size may be optimized following computed tomographic angiography and surgical delay

    Coal and Climate Change

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    This overview adopts a critical social science perspective to examine the state of play and potential futures for coal in the context of climate change. It introduces key trends in coal consumption, production and trade, before appraising the relevant literature. Finding surprisingly little literature directly focussed on coal and climate change compared with related fields, it appraises existing work and highlights key areas for future work. In addition to established bodies of work on the situated politics of coal and the political economy of coal, new work calling for demand side policies to be supplemented with supply side policies highlights the increasing importance of how normative contestations drive debates over coal, suggesting that future work needs to engage not only much more directly with climate change as an issue, but particularly with the place of coal in a just transition. Because of coal’s mammoth contribution to climate change and the complex political economy which drives its production and consumption, it is likely that coal will remain at the centre of difficult questions about the relationship between climate action and development for some time
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