143 research outputs found

    Finite fracture mechanics and cohesive crack model: Weight functions vs. cohesive laws

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    The present work represents the prosecution of a previous paper [Short cracks and V-notches: Finite Frac- ture Mechanics vs. Cohesive Crack Model (2016). P. Cornetti, A. Sapora, A. Carpinteri. Engineering Fracture Mechanics 168:2–12] aiming to corroborate the use of Finite Fracture Mechanics by showing that its fail- ure load estimates are very close to the ones provided by the well-established Cohesive Crack Model. While the above paper focused only on the Dugdale cohesive law and the original Finite Fracture Me- chanics approach, here we consider generic cohesive laws of power law type and propose an extension of Finite Fracture Mechanics based on stress weight functions. We argue that excellent agreement be- tween the models is found provided proper correspondence rules between the shape of the cohesive laws and of the weight functions are given. As a test bench for this conjecture, we choose the Griffith crack geometry, where we are able to achieve the solutions in a semi-analytical way for both the models. Finally, we show that similar results can be obtained also by varying the domain of the weight function while keeping fixed its shape

    Peierls to superfluid crossover in the one-dimensional, quarter-filled Holstein model

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    We use continuous-time quantum Monte Carlo simulations to study retardation effects in the metallic, quarter-filled Holstein model in one dimension. Based on results which include the one- and two-particle spectral functions as well as the optical conductivity, we conclude that with increasing phonon frequency the ground state evolves from one with dominant diagonal order---2k_F charge correlations---to one with dominant off-diagonal fluctuations, namely s-wave pairing correlations. In the parameter range of this crossover, our numerical results support the existence of a spin gap for all phonon frequencies. The crossover can hence be interpreted in terms of preformed pairs corresponding to bipolarons, which are essentially localised in the Peierls phase, and "condense" with increasing phonon frequency to generate dominant pairing correlations.Comment: 11 pages, 5 figure

    The fetal mouse is a sensitive genotoxicity model that exposes lentiviral-associated mutagenesis resulting in liver oncogenesis

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    This article is available open access through the publisher’s website at the link below. Copyright @ 2013 The American Society of Gene & Cell Therapy.Genotoxicity models are extremely important to assess retroviral vector biosafety before gene therapy. We have developed an in utero model that demonstrates that hepatocellular carcinoma (HCC) development is restricted to mice receiving nonprimate (np) lentiviral vectors (LV) and does not occur when a primate (p) LV is used regardless of woodchuck post-translation regulatory element (WPRE) mutations to prevent truncated X gene expression. Analysis of 839 npLV and 244 pLV integrations in the liver genomes of vector-treated mice revealed clear differences between vector insertions in gene dense regions and highly expressed genes, suggestive of vector preference for insertion or clonal outgrowth. In npLV-associated clonal tumors, 56% of insertions occurred in oncogenes or genes associated with oncogenesis or tumor suppression and surprisingly, most genes examined (11/12) had reduced expression as compared with control livers and tumors. Two examples of vector-inserted genes were the Park 7 oncogene and Uvrag tumor suppressor gene. Both these genes and their known interactive partners had differential expression profiles. Interactive partners were assigned to networks specific to liver disease and HCC via ingenuity pathway analysis. The fetal mouse model not only exposes the genotoxic potential of vectors intended for gene therapy but can also reveal genes associated with liver oncogenesis.Imperial College London, the Wellcome Trust, and Brunel University

    Harnessing the power of complex light propagation in multimode fibers for spatially resolved sensing

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    The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental effects. These properties can be a powerful tool for sensing, as small perturbations lead to significant changes in the output of the fiber. However, the mechanism to encode spatially resolved sensing information into the speckle pattern and the ability to extract this information is thus far unclear. In this paper, we demonstrate that spatially dependent mode coupling is crucial to achieving spatially resolved measurements. We leverage machine learning to quantitatively extract this spatially resolved sensing information from three fiber types with dramatically different characteristics and demonstrate that the fiber with the highest degree of spatially dependent mode coupling provides the greatest accuracy.Comment: 17 pages and 7 figure

    The Representation of Culture in “Bumi Manusia” Novel by Pramoedya Ananta Toer

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    Critical discourse analysis is a view of language in discourse analysis that views powers as always involved in forming subjects represented in language. The AWK model used in this paper is Norman Fairclough’s critical discourse analysis. Critical discourse analysis, which generally analyzes media texts, can also be used to analyze literary works, including novels. The novel analyzed by Norman Fairclough’s discourse analysis is the novel Bumi Manusia by Manusiaya Ananta Toer. Norman Fairclough’s discourse analysis examines text, discourse practice, and sociocultural practice. The three aspects of Norman Fairclough’s discourse analysis can be answered through the descriptive method text section the researcher can find three basic elements in the Norman Fairclough model, namely elements of representation, relations, and identity in the novel Bumi Manusia. Meanwhile, this paper will only discuss one element, namely representation. The result of this research is that culture is found in the text of the novel Bumi Manusia, in the form of daily behavior, language, clothes, to the names that appear in the text of the novel. In the text of the Bumi Manusia novel, there are also several cultures, not only Indonesian culture but, there is also Dutch culture by the contents of the story or synopsis of the novel describes indigenous life side by side with the Dutch

    Exploring the theories, determinants and policy-options of street vending: a demand-side approach

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    Street vending has been a common feature of urban centres for several decades, with a relatively high proportion of developing countries’ populations depending on it for employment, income or survival. Taking a supply-side approach, studies have shown that urban planners’ responses to street vending have followed the modernism theory. In this paper, we take a demand-side (buyer-focused) approach to studying street vending, which to date has received little attention from the academic community. Employing data from Lagos state, Nigeria, we report four explanations underpinning the demand-side of street vending: formal economy failures, social/redistributive, financial gains, and multifeature. These are, in turn, explained by individuals’ marital status, level of education, and perception. Our findings highlight the need for urban planners to embrace pragmatic policies in addressing these demand-side drivers of street vending and use of urban space, rather than criminalising its actors

    A Historical Investigation into Item Formats of ACS Exams and Their Relationships to Science Practices

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    The release of the NRC Framework for K-12 Science Education and the Next Generation Science Standards has important implications for classroom teaching and assessment. Of particular interest is the implementation of science practices in the chemistry classroom, and the definitions established by the NRC makes these objectives much more tangible. However, this still may leave some wondering about how to begin making these changes. Mid-twentieth century chemical educators and pioneers of the first ACS exams advocated for testing science thinking and skills as early as the 1930s, and this necessitates a discussion about how early ACS exams measured these attributes. More recent debates have seen arguments that multiple-choice questions cannot measure high levels of cognitive ability in chemistry, which leaves questions about how ACS exams or instructors who write tests for large scale classrooms might try to measure science practices. The possibility that an analysis of the item formats used on ACS exams from 1934 to 1970 would help inform the creation of improved item types in testing today is investigated and presented here.Reprinted (adapted) with permission from J. Chem. Educ., 2015, 92 (11), pp 1798–1806. Copyright 2015 American Chemical Society.</p

    National profile of foot orthotic provision in the United Kingdom, part 1 : practitioners and scope of practice.

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    Foot orthoses have been advocated in the management of a wide range of clinical foot and lower limb problems and are within the scope of podiatry, orthotic and physiotherapy practice. Previous reports into the provision of orthoses have consistently identified significant issues with services and devices, but data were never specific to foot orthoses. The aim of this first of a series of papers was to report the first ever national multi professional profile of foot orthosis provision in the United Kingdom. Quantitative and qualitative data were collected from podiatrists, orthotists and physiotherapists via an online questionnaire. The topics, questions and answers were developed through a series of pilot phases. The professions were targeted through electronic and printed materials. Data were captured over a 10 month period in 2016. A total of 499 responses were included in analysis, including 357 podiatrists, 93 orthotists and 49 physiotherapists. The results reveal wide ranging practices across podiatrists, orthotists and physiotherapists, provision of orthoses through different health care departments (uni and multidisciplinary), for different health conditions (acute and chronic), and involving different types of orthoses (prefabricated and customised). Foot orthoses in the United Kingdom are provided in areas of well recognised health and rehabilitation priorities. A wide range of orthotic devices and practices are employed and different professions provide foot orthoses in different ways

    An evidence-based review of creative problem solving tools: a practitioner’s resource

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    Creative problem solving (CPS) requires solutions to be useful and original. Typically, its operations span problem finding, idea generation and critical evaluation. The benefits of training CPS have been extolled in education, industry and government with evidence showing it can enhance performance. However, while such training schemes work, less is known about the specific tools used. Knowing whether a particular tool works or not would provide practitioners with a valuable resource, leading to more effective training schemes, and a better understanding of the processes involved. A comprehensive review was undertaken examining the empirical support of tools used within CPS. Despite the surprising lack of research focusing on the use and success of specific tools some evidence exists to support the effectiveness of a small set. Such findings present practitioners with a potential resource that could be used in a stand-alone setting or possibly combined to create more effective training programmes

    A survey of people with foot problems related to rheumatoid arthritis and their educational needs

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    Background Up to 50% of people with rheumatoid arthritis (RA) have foot symptoms at diagnosis, hence early foot health intervention is recommended and this should include patient education. This study identifies, for the first time, the foot health education (FHE) needs of people with RA. Methods An online survey of people with RA (n = 543) captured quantitative data in relation to the aims, methods of delivery, content, timing and accessibility of FHE. Results The majority concurred about the aims of FHE. Verbal delivery and websites were the most common methods. Written and verbal FHE were perceived to be the most effective methods. The point of diagnosis was the preferred time to receive it. Lack of access to FHE included minimal focus on foot health during consultations by both health practitioners and patients with RA. Participant gender, age, disease duration and living situation had a statistically significant influence on the results. Conclusion Foot health education is rarely considered within the medical consultation. There is a lack of patient and/or health professional awareness of this need with a detrimental impact on foot health. Patients require health professionals to identify their foot education health needs. Tailored foot health education should begin at initial diagnosis
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