7,428 research outputs found

    Cork–polymer biocomposites: mechanical, structural and thermal properties

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    This work addresses to the preparation of biocomposites resulting from the combination of different biodegradable aliphatic polyesters with cork (30 wt.%). The lignocellulosic biomass with closed cellular structure was compounded with poly(L-lactic acid) (PLLA), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), poly-ε-caprolactone (PCL) and starch-poly-ε-caprolactone (SPCL) blend using a twin-screw extruder prior to injection moulding into tensile samples. The physico-mechanical and thermal properties of the matrices and the bio-based cork composites were investigated. This study shows that the addition of cork contributes to produce lightweight materials using PLLA and PHBV matrices and promotes an increase on the stiffness of PCL. The fracture morphology observations showed good physical corkâ matrix bonding with absence of voids or cavities between cork and the bio-based polyesters. Cork increases the crystallinity degree of the biocomposites. These findings suggest that the corkâ polymer biocomposites are a viable alternative to develop more sustainable composite materials, such as automotive interior parts and bio-based caps for wine bottles as it has been shown as proof-of-concept.The work was performed within the project of Corticeira Amorim S.G.P.S. on the development of new products based in/with cork. The authors gratefully acknowledge the financial support, through the COMPETE/QREN/EU funding program in the project with acronym NovelComp (QREN FCOMP-01-0202-FEDER-003107). The author E.M.F. acknowledges the financial support from the Portuguese Foundation for Science and Technology (FCT) and POPH/FSE for the post-doctoral grant (SFRH/BPD/96197/2013)

    Inverse Classification for Comparison-based Interpretability in Machine Learning

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    In the context of post-hoc interpretability, this paper addresses the task of explaining the prediction of a classifier, considering the case where no information is available, neither on the classifier itself, nor on the processed data (neither the training nor the test data). It proposes an instance-based approach whose principle consists in determining the minimal changes needed to alter a prediction: given a data point whose classification must be explained, the proposed method consists in identifying a close neighbour classified differently, where the closeness definition integrates a sparsity constraint. This principle is implemented using observation generation in the Growing Spheres algorithm. Experimental results on two datasets illustrate the relevance of the proposed approach that can be used to gain knowledge about the classifier.Comment: preprin

    First validation of the gout activity score against gout impact scale in a primary care based gout cohort

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    Objectives To validate the gout activity score (GAS) against the gout impact scale in a primary care based gout cohort. Methods This was a single-centre cross-sectional study. People with gout who participated in previous research at Academic Rheumatology, University of Nottingham, UK, and consented for participation in future studies were mailed a questionnaire in September 2015. Those returning completed questionnaires were invited to attend for a study visit at which blood was collected and musculoskeletal examination was performed. The Gout Assessment Questionnaire, which contains the gout impact scale (GIS), and short form (SF) 36v2 questionnaires were completed. The GAS3-step-c score was calculated. Spearman’s correlation coefficient was calculated to examine correlation between GAS and SF-36 v2, and GIS. Statistical analyses were performed using PASW v22. Results 102 (93% men) of the 150 participants who were mailed a questionnaire attended the study visit. Their mean (SD) age, BMI, serum uric acid and GAS were 67.94 (9.93) years, 29.96 (4.57) kg/m2, 5.25 (1.75) mg/dl, and 2.99 (0.74) respectively. There was moderate correlation between GAS and gout concern overall, unmet gout treatment need, and gout concern during an attack components of GIS (r= 0.306 to 0.453), but no to poor correlation between GAS and summary scores and scales of SF-36 v2 (r= -0.090 to -0.251). Conclusion This first study to validate GAS against the GIS found moderate correlation. However, this study did not examine the predictive validity of GAS, and prospective studies are needed before GAS can be used widely

    SPIDER VII - Revealing the Stellar Population Content of Massive Early-type Galaxies out to 8Re

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    Radial trends of stellar populations in galaxies provide a valuable tool to understand the mechanisms of galaxy growth. In this paper, we present the first comprehensive analysis of optical-optical and optical-NIR colours, as a function of galaxy mass, out to the halo region (8Re) of early-type galaxies (ETGs). We select a sample of 674 massive ETGs (M*>3x10^10MSun) from the SDSS-based SPIDER survey. By comparing with a large range of population synthesis models, we derive robust constraints on the radial trends in age and metallicity. Metallicity is unambiguously found to decrease outwards, with a measurable steepening of the slope in the outer regions (Re<R<8Re). The gradients in stellar age are found to be more sensitive to the models used, but in general, the outer regions of ETGs feature older populations compared to the cores. This trend is strongest for the most massive galaxies in our sample (M*>10^11MSun). Furthermore, when segregating with respect to large scale environment, the age gradient is more significant in ETGs residing in higher density regions. These results shed light on the processes leading from the formation of the central core to the growth of the stellar envelope of massive galaxies. The fact that the populations in the outer regions are older and more metal-poor than in the core suggests a process whereby the envelope of massive galaxies is made up of accreted small satellites (i.e. minor mergers) whose stars were born during the first stages of galaxy formation.Comment: 20 pages, 13 figures, 10 tables. Accepted for publication in MNRA

    Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictides

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    The in-plane anisotropy of the electrical resistivity across the coupled orthorhombic and magnetic transitions of the iron pnictides has been extensively studied in the parent and electron-doped compounds. All these studies universally show that the resistivity ρa\rho_{a} across the long orthorhombic axis aOa_{O} - along which the spins couple antiferromagnetically below the magnetic transition temperature - is smaller than the resistivity ρb\rho_{b} of the short orthorhombic axis bOb_{O}, i. e. ρa<ρb\rho_{a}<\rho_{b}. Here we report that in the hole-doped compounds Ba1x_{1-x}Kx_{x}Fe2_{2}As2_{2}, as the doping level increases, the resistivity anisotropy initially becomes vanishingly small, and eventually changes sign for sufficiently large doping, i. e. ρb<ρa\rho_{b}<\rho_{a}. This observation is in agreement with a recent theoretical prediction that considers the anisotropic scattering of electrons by spin-fluctuations in the orthorhombic/nematic state.Comment: This paper has been replaced by the new version offering new explanation of the experimental results first reported her

    Language therapy and autism: results of three different models

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    TEMA: as dificuldades de comunicação e linguagem são elementos essenciais dos distúrbios do espectro autista, fazendo parte da tríade de sintomas utilizada para o diagnóstico. OBJETIVO: verificar a existência de diferenças observáveis a partir das características do perfil funcional da comunicação e do desempenho sócio-cognitivo de crianças e adolescentes do espectro autístico, atendidos em três diferentes situações terapêuticas, tanto no que diz respeito a um período experimental pré-determinado de intervenção, quanto na manutenção dos resultados obtidos após um igual período de tempo de atendimento fonoaudiológico regular. MÉTODO: os sujeitos foram crianças e adolescentes com diagnósticos psiquiátricos incluídos no espectro autístico em início de processos de terapia fonoaudiológica. Os participantes foram divididos em três grupos de acordo com o desenho terapêutico oferecido por um período de seis meses. RESULTADOS: não indicaram diferenças estatisticamente significativas, embora observáveis. O grupo com mais indicadores de progresso durante o período específico de intervenção diferenciada, foi o grupo A, em que os sujeitos eram atendidos em duplas. O resultado não previsto foi que não só em nenhum dos grupos foi observada diminuição dos índices obtidos, após um período de seis meses, como em algumas situações o número de sujeitos com progresso aumentou após esse período. CONCLUSÃO: os resultados do presente estudo reiteram a adequação de procedimentos de determinação do perfil individual de habilidades e inabilidades de cada sujeito como fundamentação para definições a respeito do modelo de intervenção adotado.BACKGROUND: language and communication disorders are essential features of the autistic spectrum disorders, and are part of the diagnostic criteria. AIM: to verify the existence of observable differences in the functional communicative profile and in the social cognitive performance of autistic children and adolescents receiving language therapy in three different situations. Assessment focused on the period of modified intervention and on the following period. METHOD: subjects were children and adolescents with psychiatric diagnosis within the autistic spectrum. Participants were divided in three groups according to the intervention received during a period of six months. RESULTS: determined observable differences, but not statistically significant. The group that presented the most progress was the one in which the subjects received therapy in pairs. The fact that none of groups presented a decrease in their progress indicators, as well as the fact that in a few situations the number of subjects who presented progress increased after this period was not expected. CONCLUSION: the results of the present study reinforce that the procedures used to determine the individual abilities and inabilities were useful in planning the intervention procedures.CNP

    Distribution of the heavy elements throughout the extended narrow line region of the Seyfert galaxy NGC 7212

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    The latest observations of line and continuum spectra emitted from the extended narrow line region (ENLR) of the Seyfert 2 galaxy NGC 7212 are analysed using models accounting for photoionization from the active nucleus and shocks. The results show that relatively high (500--800 \kms) shock velocities appear on the edge of the cone and outside of it. The model-inferred AGN flux, which is lower than 101110^{-11} photons cm2^{-2} s1^{-1} eV1^{-1} at the Lyman limit, is more typical of low-luminosity AGN, and less so for Seyfert 2 galaxies. The preshock densities are characteristic of the ENLR and range between 80--150 cm3^{-3}. Nitrogen and sulphur are found depleted by a factor lower than 2, particularly at the eastern edge. Oxygen is depleted at several locations. The Fe/H ratio is approximately solar, whereas the Ne/H relative abundance is unusually high, 1.5--2 times the solar value. Modelling the continuum spectral energy distribution (SED), we have found radio synchrotron radiation generated by the Fermi mechanism at the shock front, whereas the X-rays are produced by the bremsstrahlung from a relatively high temperature plasma.Comment: 17 pages, 14 figures, accepted for publication in A&

    Interactive use of communication by verbal and non-verbal autistic children

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    TEMA: comunicação de crianças autistas. OBJETIVO: avaliar a funcionalidade da comunicação de crianças incluídas no espectro autístico divididas em dois grupos (verbais e não verbais) e identificar as possíveis relações entre os grupos estudados. MÉTODO: foram sujeitos 20 crianças autistas, 10 verbais e 10 não verbais, com idade variando entre 2a e 10 m e 10a e 6m de vida. Todos os sujeitos foram gravados durante 30 minutos, em situação de interação espontânea com a mãe. O corpus das gravações dos dois grupos foi analisado quanto ao desempenho do perfil funcional de comunicação de cada sujeito, de cada grupo e as possíveis relações existentes entre os dois grupos. RESULTADOS: os dados referentes à ocupação do espaço comunicativo sugerem equilíbrio entre a comunicação da criança autista e sua mãe. Quanto ao número de atos comunicativos produzidos por minuto, nota-se que há uma visível divisão entre as crianças, que coincide com a divisão de grupos proposta: crianças autistas verbais e crianças autistas não verbais. Com relação à utilização dos meios comunicativos pelas crianças autistas observa-se que tanto as crianças autistas não verbais como as verbais fazem grande uso do meio gestual para se comunicarem. Os dados correspondentes à utilização das funções comunicativas mais inter-pessoais apontam a dificuldade da criança autista em interagir com o outro CONCLUSÃO: a caracterização do perfil funcional da comunicação realizada neste estudo confirmou a dificuldade destas crianças no estabelecimento de interações comunicativas e como essas dificuldades independem do meio comunicativo utilizado.BACKGROUND: communication of autistic children. AIM: to assess the communication functionality of verbal and non-verbal children of the autistic spectrum and to identify possible associations amongst the groups. METHOD: subjects were 20 children of the autistic spectrum divided into two groups: V with 10 verbal children and NV with 10 non-verbal children with ages varying between 2y10m and 10y6m. All subjects were video recorded during 30 minutes of spontaneous interaction with their mothers. The samples were analyzed according to the functional communicative profile and comparisons within and between groups were conducted. RESULTS: data referring to the occupation of communicative space suggest that there is an even balance between each child and his mother. The number of communicative acts per minute shows a clear difference between verbal and non-verbal children. Both verbal and non-verbal children use mostly the gestual communicative mean in their interactions. Data about the use of interpersonal communicative functions point out to the autistic children's great interactive impairment. CONCLUSION: the characterization of the functional communicative profile proposed in this study confirmed the autistic children's difficulties with interpersonal communication and that these difficulties do not depend on the preferred communicative mean

    Magnesium and aluminum sulfates in salt efflorescences from acid mine drainage in the Iberian Pyrite Belt (SW Spain)

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    Proceedings IMWA 2016, Freiberg/Germany | Drebenstedt, Carsten, Paul, Michael (eds.) | Mining Meets Water – Conflicts and Solutions.The current study is focused on AMD-precipitates that compose the typical magnesium and aluminum sulfate assemblages in the Spanish sector of the Iberian Pyrite Belt (SW Spain). The main objectives are identify and describe the composition, morphology and paragenetic relationships of these sulfate phases. From the methodological pint of view, sampling procedure covered the entire metallogenetic province, including five selected representative mines and eight river basins, which are the main receptors of the acid mine drainage discharges. The mineralogical analyses were performed by X-Ray diffraction and electron microscopy. The obtained results showed the extraordinary abundance of aluminum sulfates with acicular habit, from the series pickeringite-apjhonite-halotrichite. They form typical assemblages with other aluminum sulfates, such as alunogen and tamarugite, and with the Mg sulfates: epsomite and hexahydrite. Moreover, the paragenetic relationships indicate the late occurrence of acicular Alsulfates from the halotrichite group.Financial support for this research was provided by the Andalusian Autonomous Government Excellence Project, code P06-RNM-02167. This work was also co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by Fundação para a Ciência e Tecnologia.info:eu-repo/semantics/publishedVersio

    Acid mine drainage in semi-arid regions: the extent of the problem in the waters of reservoirs in the Iberian Pyrite Belt (SW Spain)

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    There are many reservoirs in the Iberian Pyrite Belt (IPB), SW Spain, which receive contributions from watercourses affected by acid mine drainage processes, characterised by low pH values and high concentrations of heavy metals and sulphates. When they reach the reservoirs, the waters increase its pH, which will cause most of the metal load carried by the mining channel to precipitate into the reservoir itself and accumulate on its floor. The silting of reservoirs is an environmental problem which can affect the loss of storage capacity, their general functioning and aquatic ecosystems. A study of these is vital to allow both preventative and corrective measures to be established. Climatic conditions are the most significant external controlling factors in terms of the degree and type of mining pollution. The study area presents characteristics typical of the semi-arid Mediterranean climate, with annual precipitation of around 630 mm/year; moderate temperatures with average annual values of 17.1 W C and a temperature range of 50 W C. The aim of this study is to carry out a physical–chemical characterization of the waters where they enter the reservoirs located in the IPB over the course of a hydrological year and to establish possible interdependencies between the various parameters.Financial support for this research was provided by DGCICYT National Plan, project no. CGL2010-21268-C02-01.info:eu-repo/semantics/publishedVersio
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