373 research outputs found

    Permeability and conductivity of platelet-reinforced membranes and composites

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    We present large scale simulations of the diffusion constant DD of a random composite consisting of aligned platelets with aspect ratio a/b>>1a/b>>1 in a matrix (with diffusion constant D0D_0) and find that D/D0=1/(1+c1x+c2x2)D/D_0 = 1/(1+ c_1 x + c_2 x^2), where x=avf/bx= a v_f/b and vfv_f is the platelet volume fraction. We demonstrate that for large aspect ratio platelets the pair term (x2x^2) dominates suggesting large property enhancements for these materials. However a small amount of face-to-face ordering of the platelets markedly degrades the efficiency of platelet reinforcement.Comment: RevTeX, 5 pages, 4 figures, submitted to PR

    The role of emotional resilience, childhood parentification, and attachment style on antisocial behaviour in adulthood: a comparison of an offender and normative population

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    Purpose: Despite a robust link between poor caregiver attachment and antisociality, few studies have examined the influence of parentification and emotional resilience on delinquency in later life, in groups at differing risk for antisocial conduct. Methodology: This pilot study compared the influence of parentification, attachment style (avoidant or anxious) and emotional resilience on adulthood antisocial behaviour in an offender and normative sample. Of the 137 participants in this study, 66 were supervised by the National Probation Service (age M = 36.90, SD = 13.91), and 71 were recruited from community-dwelling and student populations (age M = 31.83, SD = 13.25). Findings: In partial support of the predictions, participants in the offender group reported significantly greater levels of attachment anxiety compared to the normative group. However, emotional resilience was positively associated with antisociality in the normative sample. Research implications: This small-scale investigation indicates value in exploring these specific variables in a larger, matched samples study, to enable clearer comparisons to be made between offender and normative groups. Practical implications: The preliminary findings suggest that attachment anxiety is associated with antisociality in offender populations, which indicate a therapeutic focus on attachment anxiety as part of correctional care and offender rehabilitation. Originality: This study is novel in its aim to examine the influence of childhood parentification, attachment deficits and emotional resilience on adulthood antisociality in participants from a high-risk offender sample and non-high-risk normative sample

    Linking working memory and long-term memory: A computational model of the learning of new words

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    The nonword repetition (NWR) test has been shown to be a good predictor of children’s vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory (LTM) has been proposed. In this paper, we present a computational model of children’s vocabulary acquisition (EPAM-VOC) that specifies how phonological working memory and LTM interact. The model learns phoneme sequences, which are stored in LTM and mediate how much information can be held in working memory. The model’s behaviour is compared with that of children in a new study of NWR, conducted in order to ensure the same nonword stimuli and methodology across ages. EPAM-VOC shows a pattern of results similar to that of children: performance is better for shorter nonwords and for wordlike nonwords, and performance improves with age. EPAM-VOC also simulates the superior performance for single consonant nonwords over clustered consonant nonwords found in previous NWR studies. EPAM-VOC provides a simple and elegant computational account of some of the key processes involved in the learning of new words: it specifies how phonological working memory and LTM interact; makes testable predictions; and suggests that developmental changes in NWR performance may reflect differences in the amount of information that has been encoded in LTM rather than developmental changes in working memory capacity. Keywords: EPAM, working memory, long-term memory, nonword repetition, vocabulary acquisition, developmental change

    The Simple View of Reading Made Complex by Morphological Decoding Fluency in Bilingual Fourth-Grade Readers of English

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    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThis study examined the complexity of the Simple View of Reading focusing on morphological decoding fluency in fourth-grade readers of English in Singapore. The participants were three groups of students who all learned to become bilingual and biliterate in the English language (EL) and their respective ethnic language in school but differed in the home language they used. The first group was ethnic Chinese students who used English as the dominant home language (Chinese EL1); the other two groups were ethnic Chinese and Malay students whose dominant home language was not English but Chinese (Chinese EL2) and Malay (Malay EL2), respectively. The measures included pseudo word decoding (phonemic decoding), timed decoding of derivational words (morphological decoding fluency), oral vocabulary, and passage comprehension. Path analysis showed that oral vocabulary significantly predicted reading comprehension across all three groups; yet a significant effect of morphological decoding fluency surfaced in the Chinese EL1 and Malay EL2 groups but not the Chinese EL2 group. Multi-group path analysis and commonality analysis further confirmed that morphological decoding played a larger role in the in the Chinese EL1 and Malay EL2 groups. These findings are discussed in light of the joint influence of target language experience and cross-linguistic influence on second language or bilingual reading development.Office of Education Research, National Institute of Education, Nanyang Technological Universit

    Mechanisms underlying DMARD inefficacy in difficult-to-treat rheumatoid arthritis: a narrative review with systematic literature search

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    Management of RA patients has significantly improved over the past decades. However, a substantial proportion of patients is difficult-to-treat (D2T), remaining symptomatic after failing biological and/or targeted synthetic DMARDs. Multiple factors can contribute to D2T RA, including treatment non-adherence, comorbidities and co-existing mimicking diseases (e.g. fibromyalgia). Additionally, currently available biological and/or targeted synthetic DMARDs may be truly ineffective ('true' refractory RA) and/or lead to unacceptable side effects. In this narrative review based on a systematic literature search, an overview of underlying (immune) mechanisms is presented. Potential scenarios are discussed including the influence of different levels of gene expression and clinical characteristics. Although the exact underlying mechanisms remain largely unknown, the heterogeneity between individual patients supports the assumption that D2T RA is a syndrome involving different pathogenic mechanisms

    Factors influencing terrestriality in primates of the Americas and Madagascar

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    Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use

    Insights on bovine genetic engineering and cloning

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    Transgenic technology has become an essential tool for the development of animal biotechnologies, and animal cloning through somatic cell nuclear transfer (SCNT) enabled the generation of genetically modified animals utilizing previously modified and selected cell lineages as nuclei donors, assuring therefore the generation of homogeneous herds expressing the desired modification. The present study aimed to discuss the use of SCNT as an important methodology for the production of transgenic herds, and also some recent insights on genetic modification of nuclei donors and possible effects of gene induction of pluripotency on SCNT

    The mammalian gene function resource: The International Knockout Mouse Consortium

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    In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed highthroughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research

    Measurement of the branching ratio Γ(Λb⁰ → ψ(2S)Λ0)/Γ(Λb⁰ → J/ψΛ0) with the ATLAS detector

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    An observation of the Λb0→ψ(2S)Λ0\Lambda_b^0 \rightarrow \psi(2S) \Lambda^0 decay and a comparison of its branching fraction with that of the Λb0→J/ψΛ0\Lambda_b^0 \rightarrow J/\psi \Lambda^0 decay has been made with the ATLAS detector in proton--proton collisions at s=8 \sqrt{s}=8\,TeV at the LHC using an integrated luminosity of 20.6 20.6\,fb−1^{-1}. The J/ψJ/\psi and ψ(2S)\psi(2S) mesons are reconstructed in their decays to a muon pair, while the Λ0→pπ−\Lambda^0\rightarrow p\pi^- decay is exploited for the Λ0\Lambda^0 baryon reconstruction. The Λb0\Lambda_b^0 baryons are reconstructed with transverse momentum pT>10 p_{\rm T}>10\,GeV and pseudorapidity ∣η∣<2.1|\eta|<2.1. The measured branching ratio of the Λb0→ψ(2S)Λ0\Lambda_b^0 \rightarrow \psi(2S) \Lambda^0 and Λb0→J/ψΛ0\Lambda_b^0 \rightarrow J/\psi \Lambda^0 decays is Γ(Λb0→ψ(2S)Λ0)/Γ(Λb0→J/ψΛ0)=0.501±0.033(stat)±0.019(syst)\Gamma(\Lambda_b^0 \rightarrow \psi(2S)\Lambda^0)/\Gamma(\Lambda_b^0 \rightarrow J/\psi\Lambda^0) = 0.501\pm 0.033 ({\rm stat})\pm 0.019({\rm syst}), lower than the expectation from the covariant quark model.Comment: 12 pages plus author list (28 pages total), 5 figures, 1 table, published on Physics Letters B 751 (2015) 63-80. All figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/BPHY-2013-08
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