2,540 research outputs found

    Fixed-Parameter Algorithms for Computing RAC Drawings of Graphs

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    In a right-angle crossing (RAC) drawing of a graph, each edge is represented as a polyline and edge crossings must occur at an angle of exactly 90∘90^\circ, where the number of bends on such polylines is typically restricted in some way. While structural and topological properties of RAC drawings have been the focus of extensive research, little was known about the boundaries of tractability for computing such drawings. In this paper, we initiate the study of RAC drawings from the viewpoint of parameterized complexity. In particular, we establish that computing a RAC drawing of an input graph GG with at most bb bends (or determining that none exists) is fixed-parameter tractable parameterized by either the feedback edge number of GG, or bb plus the vertex cover number of GG.Comment: Accepted at GD 202

    Toxic Timescapes: Examining Toxicity across Time and Space

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    An interdisciplinary environmental humanities volume that explores human-environment relationships on our permanently polluted planet. While toxicity and pollution are ever present in modern daily life, politicians, juridical systems, media outlets, scholars, and the public alike show great difficulty in detecting, defining, monitoring, or generally coming to terms with them. This volume’s contributors argue that the source of this difficulty lies in the struggle to make sense of the intersecting temporal and spatial scales working on the human and more-than-human body, while continuing to acknowledge race, class, and gender in terms of global environmental justice and social inequality. The term toxic timescapes refers to this intricate intersectionality of time, space, and bodies in relation to toxic exposure. As a tool of analysis, it unpacks linear understandings of time and explores how harmful substances permeate temporal and physical space as both event and process. It equips scholars with new ways of creating data and conceptualizing the past, present, and future presence and possible effects of harmful substances and provides a theoretical framework for new environmental narratives. To think in terms of toxic timescapes is to radically shift our understanding of toxicants in the complex web of life. Toxicity, pollution, and modes of exposure are never static; therefore, dose, timing, velocity, mixture, frequency, and chronology matter as much as the geographic location and societal position of those exposed. Together, these factors create a specific toxic timescape that lies at the heart of each contributor’s narrative. Contributors from the disciplines of history, human geography, science and technology studies, philosophy, and political ecology come together to demonstrate the complex reality of a toxic existence. Their case studies span the globe as they observe the intersection of multiple times and spaces at such diverse locations as former battlefields in Vietnam, aging nuclear-weapon storage facilities in Greenland, waste deposits in southern Italy, chemical facilities along the Gulf of Mexico, and coral-breeding laboratories across the world.https://ohioopen.library.ohio.edu/oupress/1014/thumbnail.jp

    Feature Papers in Compounds

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    This book represents a collection of contributions in the field of the synthesis and characterization of chemical compounds, natural products, chemical reactivity, and computational chemistry. Among its contents, the reader will find high-quality, peer-reviewed research and review articles that were published in the open access journal Compounds by members of the Editorial Board and the authors invited by the Editorial Office and Editor-in-Chief

    LIPIcs, Volume 274, ESA 2023, Complete Volume

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    LIPIcs, Volume 274, ESA 2023, Complete Volum

    Evaluations of nutrition policy and advocacy to improve the food environment in Australia

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    Non-communicable diseases (NCDs) are the leading cause of death and disability globally. NCDs are largely preventable, with the majority attributable to four behavioural risk factors: physical inactivity, harmful use of alcohol, tobacco use and exposure to tobacco smoke, and unhealthy diets. Dietary risks are a leading mortality risk factor: eight million deaths and 188 million disability-adjusted life years each year can be attributed to dietary risks worldwide. Intervention strategies to reduce dietary risks can be broadly grouped into environmental, behavioural, or multi-component strategies. Food environment policies focus on changing the physical, social, political, or economic environment that individuals and groups live in. Policies that directly impact the food environment include food reformulation targets and nutrition standards for publicly-funded institutions. Such interventions alter food access, availability, and affordability, and can create environments that support individuals to make healthier choices. The aim of this thesis is to evaluate the design, implementation and impact of nutrition policies and advocacy strategies to improve the food environment in Australia and globally. Formative research included two secondary analyses of a global review of salt reduction programs to understand the extent and scope of national reformulation strategies and nutrition standards for publicly funded institutions, including whether these policies are designed in line with current evidence. This was followed by comprehensive policy analyses of the Australian Government’s Healthy Food Partnership reformulation strategy and state- and territory-based nutrition standards for publicly funded institutions to evaluate policy design, potential impact, and scope for strengthening policies. Finally, a five-study, mixed methods evaluation of the Victorian Salt Reduction Partnership’s (VSRP) advocacy program was undertaken to evaluate the program’s design and implementation, and the impact on the food environment. This work found that one-third of countries globally had sodium reformulation programs and a similar number had institutional nutrition standards. Most policies were in high-income countries, and Europe was the region with the highest number of policies. Policy design was highly variable and substantial opportunity to better align policies with best practice evidence and global guidance was highlighted. These opportunities include applying sodium reduction targets to a wider range of foods using the World Health Organization’s global sodium benchmarks and applying school nutrition standards to all types of publicly funded institutions. There is ample opportunity to increase the public health impact of Australian food environment policies through alignment with evidence of best practice globally. The majority of government-led reformulation targets were determined to be too conservative, and therefore likely to have limited impact on the food supply. For most food categories, more than 43% of products were already meeting the reformulation targets prior to implementation, a greater than 10% difference from the government-proposed criteria of one-third. There were also no plans for implementation, monitoring, or evaluation. The design of institutional nutrition policies may be a barrier to implementation and prevent the policies from having their intended impact: policy designs were complex, many lacked key components such as accountability mechanisms, and there were differences within and between institution types and jurisdictions. The five-study evaluation of the VSRP advocacy strategy demonstrated the multi-faceted sodium reduction program had no impact on reducing sodium levels in the food supply or government policy; however, short-term objectives (e.g., project outputs) were achieved and important lessons were generated that will be useful for future public health partnerships and interventions. The establishment of a Partnership or guiding coalition with diverse skills and experience facilitated collaborative action, capacity building and execution of the intervention. Continual monitoring and evaluation of implementation informed strategy adaptations that allowed optimisation of the Partnership strategy. The political advocacy strategy, which involved advocating for stringent government-led sodium reformulation targets, enabled the dissemination of VSRP resources to food manufacturers, although had little impact on strengthening the draft targets. The media advocacy strategy, which involved the dissemination of sodium-monitoring data through media releases, was a useful tool to gain access to the media and reach consumers with salt reduction messages, and to engage food manufacturers in discussions about salt reduction. However, in the absence of an established government reformulation policy, this food industry engagement did not translate into meaningful reductions in sodium in the packaged food supply. More effective communication between strategic and implementation partners could have improved program implementation and outcomes. Greater emphasis on developing and maintaining relationships with policymakers could have increased influence on government policy and public health impact. Existing institutional nutrition policies in Victoria also require strengthening through improvements to policy design, governance, and support services, and overcoming barriers within and external to implementing organisations, to propel state-wide progress. Overall, this thesis identified substantial scope to accelerate the local and global impact of food environment policies. In addition to improving the design of food environment policies in line with best practice evidence and global guidance, implementation of food environment policies could be strengthened through the provision of support services, step-by-step guidance, and additional tools/resources. Further, performance measurement methods need to be integrated into policy monitoring systems to enhance evaluation approaches and facilitate policy enforcement. Strong government leadership and regular monitoring of measurable goals are essential elements of successful policies. Three step-wise frameworks were developed from the evidence generated and lessons learnt in this thesis to support i) governments to design impactful food environment policies and monitor them, ii) end-users to effectively implement food environment policies and iii) public health professionals to persuasively advocate for food environment policies. Thus, this thesis will be useful for informing future public health partnerships, interventions, and government policies to reduce the global burden of diet-related NCDs

    Identifying Cluttering Edges in Near-Planar Graphs

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    Planar drawings of graphs tend to be favored over non-planar drawings. Testing planarity and creating a planar layout of a planar graph can be done in linear time. However, creating readable drawings of nearly planar graphs remains a challenge. We therefore seek to answer which edges of nearly planar graphs create clutter in their drawings generated by mainstream graph drawing algorithms. We present a heuristic to identify problematic edges in nearly planar graphs and adjust their weights in order to produce higher quality layouts with spring-based drawing algorithms. Our experiments show that our heuristic produces significantly higher quality drawings for augmented grid graphs, augmented triangulations, and deep triangulations

    Computational Modelling of Concrete and Concrete Structures

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    Computational Modelling of Concrete and Concrete Structures contains the contributions to the EURO-C 2022 conference (Vienna, Austria, 23-26 May 2022). The papers review and discuss research advancements and assess the applicability and robustness of methods and models for the analysis and design of concrete, fibre-reinforced and prestressed concrete structures, as well as masonry structures. Recent developments include methods of machine learning, novel discretisation methods, probabilistic models, and consideration of a growing number of micro-structural aspects in multi-scale and multi-physics settings. In addition, trends towards the material scale with new fibres and 3D printable concretes, and life-cycle oriented models for ageing and durability of existing and new concrete infrastructure are clearly visible. Overall computational robustness of numerical predictions and mathematical rigour have further increased, accompanied by careful model validation based on respective experimental programmes. The book will serve as an important reference for both academics and professionals, stimulating new research directions in the field of computational modelling of concrete and its application to the analysis of concrete structures. EURO-C 2022 is the eighth edition of the EURO-C conference series after Innsbruck 1994, Bad Gastein 1998, St. Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St. Anton am Arlberg 2014, and Bad Hofgastein 2018. The overarching focus of the conferences is on computational methods and numerical models for the analysis of concrete and concrete structures

    Analysis and Characterisation of Plasma Treated PEEK Scaffolds and their Implementation in Radiotherapy

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    Bone sarcomas are a present as tumours which occur in bones and soft tissues. Bone must often be removed during the treatment of these cancers and a replacement bone scaffold must be implanted to heal and bridge the removed tissue. Titanium stands as the most popular implant as a general orthopaedic implant due to its impressive mechanical properties and bio-compatibility. However, the high stiffness also poses problems due to the material mismatch with bone and can cause aseptic loosening at the interface, potentially leading to implant failure. In radiotherapy, titanium perturbs radiation beams and compromises both radiotherapy and imaging beams as well as damaging the osseointegrating cells. Our solution is to 3D print scaffolds out of Poly-ether-ether-ketone (PEEK), a biocompatible polymer already used in orthopaedics

    Xenopus

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    This book focuses on the amphibian, Xenopus, one of the most commonly used model animals in the biological sciences. Over the past 50 years, the use of Xenopus has made possible many fundamental contributions to our knowledge in cell biology, developmental biology, molecular biology, and neurobiology. In recent years, with the completion of the genome sequence of the main two species and the application of genome editing techniques, Xenopus has emerged as a powerful system to study fundamental disease mechanisms and test treatment possibilities. Xenopus has proven an essential vertebrate model system for understanding fundamental cell and developmental biological mechanisms, for applying fundamental knowledge to pathological processes, for deciphering the function of human disease genes, and for understanding genome evolution. Key Features Provides historical context of the contributions of the model system Includes contributions from an international team of leading scholars Presents topics spanning cell biology, developmental biology, genomics, and disease model Describes recent experimental advances Incorporates richly illustrated diagrams and color images Related Titles Green, S. L. The Laboratory Xenopus sp. (ISBN 978-1-4200-9109-0) Faber, J. & P. D. Nieuwkoop. Normal Table of Xenopus laevis (Daudin): A Systematical & Chronological Survey of the Development from the Fertilized Egg till the End of Metamorphosis (ISBN 978-0-8153-1896-5) Jarret, R. L. & K. McCluskey. The Biological Resources of Model Organisms (ISBN 978-1-0320-9095-5
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