626 research outputs found

    Oxide thermoelectrics prepared by laser melting: effects of processing atmosphere

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    Traditional thermoelectric materials suffer from two main problems, the toxicity/scarcity of the elements used and their stability at high temperatures or in non-inert atmospheres. Thermoelectric oxides appear to be a promising alternative to traditional materials due to natural abundance of the constituents and high thermal stability. This work focuses on the processing of these materials using the Laser Floating Zone (LFZ) technique. Particular emphasis is given to LFZ processing under various redox atmospheres, allowing unique opportunities for tuning the structural, microstructural and thermoelectric properties. This technique allows the growth of fully dense fibres, as well as the formation of metastable phases and/or promoting different oxidation states by adjusting the growth conditions. Here we report the processing of model manganite- and titanate-based materials including donorsubstituted Ca(Pr)MnO3 and Ti(Ta)O2 systems. XRD/SEM/EDS studies demonstrate some guidelines for tuning the phase composition and microstructure by adjusting the growth rate under different redox conditions. We report high power factor values of 303 μWm-1K -2 at 1120 K for the Ca(Pr)MnO3 system and 317 μWm-1K -2 for the Ti(Ta)O2 system. The obtained results suggest that LFZ is a suitable technique for processing thermoelectric oxides if optimized control over growth parameters and re-equilibration conditions is imposed.publishe

    Immature stages of the Selaginella-feeding Euptychia mollina(Nymphalidae: Satyrinae) from the Brazilian Amazon

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    The present paper describes the immature stages of the Neotropical satyrine butterfly Euptychia mollina (Hubner, [1813]) from the Brazilian Amazon Forest. Eggs were laid singly on the under surface of the fronds of its host plant, Selaginella sp. (Bryophyta: Selaginellaceae). Larvae are solitary in all instars, presenting a color pattern and shape that make them cryptic on its host plant. The pupa is short, smooth and varies from rusty brown to green. Despite the lack of a close phylogenetic relationship, larvae of Euptychia are very similar to those of the paleotropical satyrines Ragadia and Acrophtalmia, suggesting that camouflage is likely to be one of the factors explaining the similarities among them36CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP563332/2010-7; 302585/2011-7; 421248/2017-3sem informação2016/15873-8; 2011/50225-3This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES – Finance Code 001). EPB thanks Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for a post-doc fellowship (FAPESP 2016/15873-8). AVLF acknowledges support from FAPESP (Biota-Fapesp – grants 2011/50225-3), from the Conselho Nacional de Desenvolvimen-to Científico e Tecnológico (CNPq fellowship 302585/2011-7, 421248/2017-3), from the National Science Foundation (DEB-1256742) and from the United States Agency for International Development – USAID/the U.S. National Academy of Sciences (NAS), under the PEER program (Sponsor Grant Award Num-ber: AID-OAA-A-11-00012) (Mapping and Conserving Butterfly Biodiversity in the Brazilian Amazon). This publication is part of the RedeLep ‘Rede Nacional de Pesquisa e Conservação de Lepidópteros’ SISBIOTA-Brasil/CNPq (563332/2010-7). Butterfly species are registered in the SISGEN (A4E702A

    Second-order Democratic Aggregation

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    Aggregated second-order features extracted from deep convolutional networks have been shown to be effective for texture generation, fine-grained recognition, material classification, and scene understanding. In this paper, we study a class of orderless aggregation functions designed to minimize interference or equalize contributions in the context of second-order features and we show that they can be computed just as efficiently as their first-order counterparts and they have favorable properties over aggregation by summation. Another line of work has shown that matrix power normalization after aggregation can significantly improve the generalization of second-order representations. We show that matrix power normalization implicitly equalizes contributions during aggregation thus establishing a connection between matrix normalization techniques and prior work on minimizing interference. Based on the analysis we present {\gamma}-democratic aggregators that interpolate between sum ({\gamma}=1) and democratic pooling ({\gamma}=0) outperforming both on several classification tasks. Moreover, unlike power normalization, the {\gamma}-democratic aggregations can be computed in a low dimensional space by sketching that allows the use of very high-dimensional second-order features. This results in a state-of-the-art performance on several datasets

    Chronic interstitial pneumonitis

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    A patologia pulmonar intersticial compreende um grupo de doenças crónicas caracterizadas por alterações das paredes alveolares e perda das unidades funcionais alveolocapilares. São doenças raras nas crianças, na sua maioria de causa desconhecida e revestindo-se habitualmente de uma elevada morbimortalidade, dada a pouca eficácia da terapêutica actualmente disponível. Os autores descrevem o caso clínico de uma criança de 3 anos, previamente saudável, que no contexto de uma infecção respiratória desenvolve um quadro de sibilância e insuficiência respiratória grave, na investigação do qual é diagnosticada uma pneumonite intersticial crónica. Foram tentadas diversas terapêuticas (corticoterapia sistémica, hidroxicloroquina, N-acetilcisteína) sem melhoria evidente.Interstitial lung disease includes a group of chronic diseases characterized by alterations in alveolar walls and loss of functional alveolar-capillary units. These are rare diseases in children, mostly with an unknown cause and associated with a high morbidity and mortality due to insufficient therapeutic effectiveness. The authors report a case of a previously healthy 3 years old child who presented with wheezing and severe respiratory insufficiency following a respiratory infection. The investigation performed led to the diagnosis of chronic interstitial pneumonitis. Several treatments have been tried (corticosteroids,hydroxychloroquine, N-acetylcysteine) without any obvious improvement

    Value of systolic pulmonary arterial pressure as a prognostic factor of death in the systemic sclerosis EUSTAR population.

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    The aim of this study was to assess the prognostic value of systolic pulmonary artery pressure (sPAP) estimated by echocardiography in the multinational European League Against Rheumatism Scleroderma Trial and Research (EUSTAR) cohort.Data for patients with echocardiography documented between 1 January 2005 and 31 December 2011 were extracted from the EUSTAR database. Stepwise forward multivariable statistical Cox pulmonary hypertension analysis was used to examine the independent effect on survival of selected variables.Based on our selection criteria, 1476 patients were included in the analysis; 87\% of patients were female, with a mean age of 56.3 years (s.d. 13.5) and 31\% had diffuse SSc. The mean duration of follow-up was 2.0 years (s.d. 1.2, median 1.9). Taking index sPAP of 50 mmHg. In a multivariable Cox model, sPAP and the diffusing capacity for carbon monoxide (DLCO) were independently associated with the risk of death [HR 1.833 (95\% CI 1.035, 3.247) and HR 0.973 (95\% CI 0.955, 0.991), respectively]. sPAP was an independent risk factor for death with a HR of 3.02 (95\% CI 1.91, 4.78) for sPAP ≥36 mmHg.An estimated sPAP >36 mmHg at baseline echocardiography was significantly and independently associated with reduced survival, regardless of the presence of pulmonary hypertension based on right heart catheterization

    A replication study confirms the association of TNFSF4 (OX40L) polymorphisms with systemic sclerosis in a large European cohort

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    <p><b>Objectives</b> The aim of this study was to confirm the influence of TNFSF4 polymorphisms on systemic sclerosis (SSc) susceptibility and phenotypic features.</p> <p><b>Methods</b> A total of 8 European populations of Caucasian ancestry were included, comprising 3014 patients with SSc and 3125 healthy controls. Four genetic variants of TNFSF4 gene promoter (rs1234314, rs844644, rs844648 and rs12039904) were selected as genetic markers.</p> <p><b>Results</b> A pooled analysis revealed the association of rs1234314 and rs12039904 polymorphisms with SSc (OR 1.15, 95% CI 1.02 to 1.31; OR 1.18, 95% CI 1.08 to 1.29, respectively). Significant association of the four tested variants with patients with limited cutaneous SSc (lcSSc) was revealed (rs1234314 OR 1.22, 95% CI 1.07 to 1.38; rs844644 OR 0.91, 95% CI 0.83 to 0.99; rs844648 OR 1.10, 95% CI 1.01 to 1.20 and rs12039904 OR 1.20, 95% CI 1.09 to 1.33). Association of rs1234314, rs844648 and rs12039904 minor alleles with patients positive for anti-centromere antibodies (ACA) remained significant (OR 1.23, 95% CI 1.10 to 1.37; OR 1.12, 95% CI 1.01 to 1.25; OR 1.22, 95% CI 1.07 to 1.38, respectively). Haplotype analysis confirmed a protective haplotype associated with SSc, lcSSc and ACA positive subgroups (OR 0.88, 95% CI 0.82 to 0.96; OR 0.88, 95% CI 0.80 to 0.96; OR 0.86, 95% CI 0.77 to 0.97, respectively) and revealed a new risk haplotype associated with the same groups of patients (OR 1.14, 95% CI 1.03 to 1.26; OR 1.20, 95% CI 1.08 to 1.35; OR 1.23, 95% CI 1.07 to 1.42, respectively).</p> <p><b>Conclusions</b> The data confirm the influence of TNFSF4 polymorphisms in SSc genetic susceptibility, especially in subsets of patients positive for lcSSc and ACA.</p&gt
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