1,222 research outputs found

    A {3,2}-Order Bending Theory for Laminated Composite and Sandwich Beams

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    A higher-order bending theory is derived for laminated composite and sandwich beams thus extending the recent {1,2}-order theory to include third-order axial effect without introducing additional kinematic variables. The present theory is of order {3,2} and includes both transverse shear and transverse normal deformations. A closed-form solution to the cylindrical bending problem is derived and compared with the corresponding exact elasticity solution. The numerical comparisons are focused on the most challenging material systems and beam aspect ratios which include moderate-to-thick unsymmetric composite and sandwich laminates. Advantages and limitations of the theory are discussed

    How young children integrate information sources to infer the meaning of words

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    Predicting pragmatic cue integration in adults’ and children’s inferences about novel word meanings

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    Language is learned in complex social settings where listeners must reconstruct speakers’ intended meanings from context. To navigate this challenge, children can use pragmatic reasoning to learn the meaning of unfamiliar words. A critical challenge for pragmatic reasoning is that it requires integrating multiple information sources, which have typically been studied separately. Here we study this integration process. First, we experimentally isolate two sources of pragmatic information: expectations about informative communication and common ground. Next, we use a probabilistic model of conversational reasoning to formalize how these information sources should be combined and how this process might develop. We use this model to generate quantitative predictions, which we test against new experimental data from 3- to 5-year-old children (N = 243) and adults (N = 694). Results show close alignment between model predictions and data. Furthermore, the model provided a better explanation of the data compared with simpler alternative models assuming that participants selectively ignore one information source. This work integrates distinct sets of findings regarding information sources for early language learning and suggests that pragmatic reasoning models can provide a quantitative framework for understanding developmental changes in language learning

    Great ape communication as contextual social inference: a computational modelling perspective

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    Human communication has been described as a contextual social inference process. Research into great ape communication has been inspired by this view to look for the evolutionary roots of the social, cognitive and interactional processes involved in human communication. This approach has been highly productive, yet it is partly compromised by the widespread focus on how great apes use and understand individual signals. This paper introduces a computational model that formalizes great ape communication as a multi-faceted social inference process that integrates (a) information contained in the signals that make up an utterance, (b) the relationship between communicative partners and (c) the social context. This model makes accurate qualitative and quantitative predictions about real-world communicative interactions between semi-wild-living chimpanzees. When enriched with a pragmatic reasoning process, the model explains repeatedly reported differences between humans and great apes in the interpretation of ambiguous signals (e.g. pointing or iconic gestures). This approach has direct implications for observational and experimental studies of great ape communication and provides a new tool for theorizing about the evolution of uniquely human communication. This article is part of the theme issue ‘Revisiting the human ‘interaction engine’: comparative approaches to social action coordination’

    Full-field strain reconstruction using uniaxial strain measurements: Application to damage detection

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    This work investigates the inverse problem of reconstructing the continuous displacement field of a structure using a spatially distributed set of discrete uniaxial strain data. The proposed technique is based on the inverse Finite Element Method (iFEM), which has been demonstrated to be suitable for full-field displacement, and subsequently strain, reconstruction in beam and plate structures using discrete or continuous surface strain measurements. The iFEM uses a variationally based approach to displacement reconstruction, where an error functional is discretized using a set of finite elements. The effects of position and orientation of uniaxial strain measurements on the iFEM results are investigated, and the use of certain strain smoothing strategies for improving reconstruction accuracy is discussed. Reconstruction performance using uniaxial strain data is examined numerically using the problem of a thin plate with an internal crack. The results obtained highlight that strain field reconstruction using the proposed strategy can provide useful information regarding the presence, position, and orientation of damage on the plate

    Ideating IDNA: Lessons and Limitations From Leeches in Legacy Collections

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    Indirect methods for conducting faunal inventories present great promise, and genomic inventories derived from environmental sources (eDNA) are improving. Invertebrate ingested DNA (iDNA) from terrestrial leeches in the family Haemadipsidae has shown potential for surveying vertebrates and biodiversity monitoring in protected areas. Here we present an initial, and critical, evaluation of the limitations and biases of current iDNA protocols for biodiversity monitoring using both standard and NGS barcoding approaches. Key findings include the need for taxon relevant multi-locus markers and reference databases. In particular, the limitations of available reference databases have profound potential to mislead and bias eDNA and iDNA results if not critically interpreted. Nevertheless, there is great potential for recovery of amplifiable DNA from gut contents of invertebrate museum specimens which may reveal both temporal patterns and cryptic diversity in protected areas with increased efficiency. Our analyses of ingested DNA (iDNA) from both freshly stored and previously collected (legacy) samples of terrestrial leeches successfully identified vertebrates from Myanmar, Australia and Madagascar and indicate the potential to characterize microbial communities, pathogen diversity and interactions at low cost

    Environment of Er in a-Si:H: co-sputtering versus ion implantation

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    We report a comparative Extended X-Ray Fine Structure (EXAFS) study of Er in a-Si:H prepared by Er implantation in a-Si:H and by co-sputtering undergoing the same cumulative annealing processes. It was found that the Er environment in as-implanted samples is formed by Si atoms, which are replaced by oxygen under annealing. In the co-sputtered samples, the initial low coordination oxygen environment evolves under thermal treatment to an Er2O3 -like neighborhood.756759Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Development policy planning in Ghana: The case of health care provision

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    This paper examines the historical development of health policy in Ghana within the framework of financial, geographical accessibility and the availability of health care. Historically, health policy has been urban biased, and largely focused on financial accessibility. Even Nkrumah's free health care policy could not adequately address the problem of inadequate health professionals and facilities in the rural areas.The study also established that poverty is also largely a rural phenomenon.The poor benefit less from the National Health Insurance Scheme (NHIS). This situation makes the NHIS lack social equity, the very reason for its being. We recommend that government should expand health facilities in the rural areas, and introduce attractive incentive packages to attract and retain health professionals in such areas. There is an urgent need for rigorous criteria to be developed by the NHIS to identify the very poor for health insurance premium exemptions

    The Kindred Bonds of Mentally Ill Homeless Persons

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    While the unraveling of the kinship bond has long been suspected to play a role in the epidemiology of homelessness, the connection between kinship and homelessness has been little studied. Based on a normative analysis of the role of family structure in response to adversity, this article explores the impact of the amount and quality of kinship ties on episodes of homelessness experienced by discharged psychiatric patients in Ohio. Survey data derived from personal interviews with both former patients and their kin indicate more strain in relations with kin of the homeless than the nonhomeless. The strain in the kinship bond appears to emanate from a greater prevalence of chronic disabilities that undermine independent functioning and tax the resources of relatives who choose to remain involved. Consistent with this interpretation, patients with histories of homelessness reported more psychiatric symptoms, more deficits in daily living skills, and more contact with the criminal justice system. In general, patient variables were better able than family variables to differentiate the homeless from the nonhomeless. Nonetheless, the formulation of public policies for reducing the incidence and prevalence of homelessness will surely need to take account of the kinship bond and how it can be strengthened
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