198 research outputs found

    Improvement of pentathiophene/fullerene planar heterojunction organic photovoltaic cells through MoO3/CuI anode buffer bilayer

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    Organic photovoltaic cells (OPVCs) are based on a heterojunction electron donor (ED)/electron acceptor (EA). In the present work, the electron donor which is also the absorber of light is pentathiophene. The typical cells were ITO/ABL/Pentathiophene/fullerene /Alq3/Al with ABL = MoO3, CuI, MoO3/CuI. After optimisation of the pentathiophene thickness, 70 nm, the highest efficiency, 0.81%, is obtained with the bilayer MoO3/CuI as ABL. In order to understand these results the pentathiophene films deposited onto the different ABLs were characterized by scanning electron microscopy, atomic force microscopy, X-rays diffraction, optical absorption and electrical characterization. It is shown that CuI improves the conductivity of the pentathiophene layer through the modification of the film structure, while MoO3 decreases the leakage current. Using the bilayer MoO3/CuI allows cumulating the advantages of each layer

    ASPECTOS HISTÓRICOS DA ADMINISTRAÇÃO ESCOLAR NO BRASIL: APROXIMAÇÕES

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    Este estudo é parte de pesquisa mais ampla onde investigamos as relações do perfil do gestor e da gestão com o rendimento escolar aferido pelas avaliações em larga escala. Neste recorte trazemos parte do histórico da administração escolar no Brasil, tendo como objetivo contribuir com a análise da bibliografia produzida na área sobre as origens da gestão escolar e educacional brasileira. O método empregado foi a revisão bibliográfica e a análise documental com leitura flutuante e cotejamento crítico entre autores. A problemática, bem como os objetivos, visa compreender a história da administração escolar e educacional no Brasil. Como resultados, temos indícios de permanências e rupturas no processo. As permanência estão vinculadas, principalmente, as influencias externas, enquanto que as rupturas vinculam-se a evolução conceitual sobre a gestão da educação

    Magnetic dipole probes of the sd and pf shell crossing in the A=36,38 argon isotopes

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    We have calculated the M1 strength distributions in the A=36,38 argon isotopes within large-scale shell model studies which consider valence nucleons in the sd and pf shells. While the M1 strength in 36Ar is well reproduced within the sd shell, the experimentally observed strong fragmentation of the M1 strength in 38Ar requires configuration mixing between the sd and the pf shells adding to our understanding of correlations across the N=20 shell gap.Comment: 14 pages, 8 figure

    The importance of acoustic background modelling in CNN-based detection of the neotropical White-lored Spinetail (Aves, Passeriformes, Furnaridae)

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    Machine learning tools are widely used in support of bioacoustics studies, and there are numerous publications on the applicability of convolutional neural networks (CNNs) to the automated presence-absence detection of species. However, the relation between the merit of acoustic background modelling and the recognition performance needs to be better understood. In this study, we investigated the influence of acoustic background substance on the performance of the acoustic detector of the White-lored Spinetail (Synallaxis albilora). Two detector designs were evaluated: the 152-layer ResNet with transfer learning and a purposely created CNN. We experimented with acoustic background representations trained with season-specific (dry, wet, and all-season) data and without explicit modelling to evaluate its influence on the detection performance. The detector permits monitoring of the diel behaviour and breeding time of White-lored Spinetail solely based on the changes in the vocal activity patterns. We report an advantageous performance when background modelling is used, precisely when trained with all-season data. The highest classification accuracy (84.5%) was observed for the purposely created CNN model. Our findings contribute to an improved understanding of the importance of acoustic background modelling, which is essential for increasing the performance of CNN-based species detectors.This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) under Grant [CAPES-01]; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Germany

    Towards Structure-Property-Function Relationships for Eumelanin

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    We discuss recent progress towards the establishment of important structure-property-function relationships in eumelanins - key functional bio-macromolecular systems responsible for photo-protection and immune response in humans, and implicated in the development of melanoma skin cancer. We focus on the link between eumelanin's secondary structure and optical properties such as broad band UV-visible absorption and strong non-radiative relaxation; both key features of the photo-protective function. We emphasise the insights gained through a holistic approach combining optical spectroscopy with first principles quantum chemical calculations, and advance the hypothesis that the robust functionality characteristic of eumelanin is related to extreme chemical and structural disorder at the secondary level. This inherent disorder is a low cost natural resource, and it is interesting to speculate as to whether it may play a role in other functional bio-macromolecular systems.Comment: 19 pages, 8 figures, Invited highlight article for Soft Matte

    Adapting evidence-informed complex population health interventions for new contexts : a systematic review of guidance

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    Background Adapting interventions that have worked elsewhere can save resources associated with developing new interventions for each specific context. While a developing body of evidence shows benefits of adapted interventions compared with interventions transported without adaptation, there are also examples of interventions which have been extensively adapted, yet have not worked in the new context. Decisions on when, to what extent, and how to adapt interventions therefore are not straightforward, particularly when conceptualising intervention effects as contingent upon contextual interactions in complex systems. No guidance currently addresses these questions comprehensively. To inform development of an overarching guidance on adaptation of complex population health interventions, this systematic review synthesises the content of the existing guidance papers. Methods We searched for papers published between January 2000 and October 2018 in 7 bibliographic databases. We used citation tracking and contacted authors and experts to locate further papers. We double screened all the identified records. We extracted data into the following categories: descriptive information, key concepts and definitions, rationale for adaptation, aspects of adaptation, process of adaptation, evaluating and reporting adapted interventions. Data extraction was conducted independently by two reviewers, and retrieved data were synthesised thematically within pre-specified and emergent categories. Results We retrieved 6694 unique records. Thirty-eight papers were included in the review representing 35 sources of guidance. Most papers were developed in the USA in the context of implementing evidence-informed interventions among different population groups within the country, such as minority populations. We found much agreement on how the papers defined key concepts, aims, and procedures of adaptation, including involvement of key stakeholders, but also identified gaps in scope, conceptualisation, and operationalisation in several categories. Conclusions Our review found limitations that should be addressed in future guidance on adaptation. Specifically, future guidance needs to be reflective of adaptations in the context of transferring interventions across countries, including macro- (e.g. national-) level interventions, better theorise the role of intervention mechanisms and contextual interactions in the replicability of effects and accordingly conceptualise key concepts, such as fidelity to intervention functions, and finally, suggest evidence-informed strategies for adaptation re-evaluation and reporting

    Simple to be Useful: Ecosystem Base for Coastal Management

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    Os processos de Gerenciamento Costeiro (GC) nas últimas décadas vêm evoluindo, apresentando diferentes métodos de gestão, sendo que uma nova fronteira se encontra na Gestão com Base Ecossistêmica (GBE). No entanto, para colocar em prática a GBE, a qual leva em consideração as funções, os processos e os serviços ecossistêmicos dos ambientes costeiros e marinhos, entendendo-os como um conjunto de ecossistemas compostos por elementos ecológicos (naturais), econômicos e sociais, se faz necessária a base de informação ecossistêmica. O presente trabalho propõe, apresentando resultados aplicados, um roteiro metodológico de seis etapas: 1. Identificar os ecossistemas como “Unidades de Gestão”; 2. Mapear, modelar e simular os ecossistemas; 3. Identificar e classificar os serviços ecossistêmicos; 4. Definir os valores e a qualidade dos serviços; 5. Identificar os espaços de gestão; e 6. Integrar com políticas e demais instrumentos de gestão e legais. As aplicações práticas apresentadas vão desde trabalhos acadêmicos de identificação e caracterização de ambientes costeiros e marinhos a aplicações nos processos de gestão ambiental portuários, passando também pelo desenvolvimento de Zoneamentos Ecológico-Econômicos (ZEEs) em nível regional, por exemplo. Na apreciação integral do conjunto de exemplos e iniciativas para todas as etapas do modelo, depreende-se que a sua aplicação é ampla, variada e consideravelmente simples. Da mesma forma, a multiplicidade de possíveis aplicações do modelo em ações voltadas ao suporte de uma GBE sugere que seu uso pode crescer e buscar iniciativas inovadoras. A expectativa dos autores é de que tal ferramenta possa, de fato, delinear e estimular pesquisas e aplicações com base ecossistêmica na busca da sustentabilidade da costa e do bem-estar de seus atores sociais.In the last decades Coastal Management (CM) processes have been evolving, presenting different management methods, and the new frontier is at the so-called Ecosystem Based Management (EBM). However, to put into practice EBM, which takes into account ecosystem functions, processes and services of coastal and marine environments, understanding them as a set of ecosystems composed of ecological (natural), economic and social elements, it is necessary an ecosystem-based information. The present work proposes, presenting practical results, a methodological path of six stages: 1. Identification of ecosystems as "Management Units"; 2. Mapping, modeling and simulating ecosystems and their connections; 3. Identification and classification of ecosystem services; 4. Definition of values and quality of services; 5. Identification of related management procedures; and 6. Integration with policies and other management and legal tools. The concrete applications range from academic studies of identification and characterization of coastal and marine environments, to port’s environmental management processes, and the development of ecological-economic zoning at regional level, for example. In the full appreciation of the set of examples and initiatives for all stages of the model, it can be concluded that its application is wide, varied and considerably simple. Likewise, the multiplicity of possible applications of the model in practical actions aimed to support of an EBM, suggests that its use can grow and pursue innovative initiatives. The authors' expectation is that such a tool may, in fact, delineate and stimulate research and applications based on ecosystems in the quest for the sustainability of the coast and the well-being of its social actors

    Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production

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    Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width—related to its lifetime—is an important parameter. One way to determine this quantity is to measure its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here we report evidence for such off-shell contributions to the production cross-section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at the 95% confidence level. The scenario with no off-shell contribution is excluded at a p-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as Γ\GammaH_H=3.21.7+2.4^{+2.4}_{−1.7}MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs

    Search for new particles in an extended Higgs sector with four b quarks in the final state at √s = 13 TeV

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    A search for a massive resonance X decaying to a pair of spin-0 bosons ϕ that themselves decay to pairs of bottom quarks, is presented. The analysis is restricted to the mass ranges from 25 to 100 GeV and from 1 to 3 TeV. For these mass ranges, the decay products of each ϕ boson are expected to merge into a single large-radius jet. Jet substructure and flavor identification techniques are used to identify these jets. The search is based on CERN LHC proton-proton collision data at , collected with the CMS detector in 2016–2018, corresponding to an integrated luminosity of 138 . Model-specific limits, where the two new particles arise from an extended Higgs sector, are set on the product of the production cross section and branching fraction for as a function of the resonances' masses, where both the and branching fractions are assumed to be 100%. These limits are the first of their kind on this process, ranging between 30 and 1 fb at 95% confidence level for the considered mass ranges
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