9,916 research outputs found

    Inference of oxygen vacancies in hydrothermal Na0.5Bi0.5TiO3

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    A high-resolution x-ray powder diffraction study has been made of pseudo-rhombohedral and tetragonal phases in Na0.5Bi0.5TiO3 (NBT), produced via hydrothermal and conventional solidstate methods. Hydrothermal NBT exhibits significantly greater structural distortion at room temperature than solid-state NBT. Peak widths and superstructure peak intensities show a phase transition at 305 C, with trends suggesting that the structure tends towards cubic symmetry at this temperature. Structural refinements indicate that the transition occurs via a phase coexistence region with no clear intermediate phase. Piezoelectric data show evidence of polarisation pinning in hydrothermal NBT, interpreted as a high proportion of oxygen vacancies

    Social and economic impact of a PDO cheese (“Queijo de Nisa”) on the local cheese production and processing (North of Alentejo, Portugal)

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    O presente documento foi apresentado na 2nd International Conference of the LSIRD Network que decorreu em Bray, Dublin em Dezembro de 1998, tendo integrado os respectivos Proceedings.The “Queijo de Nisa” is a traditional Portuguese half-hard cheese made from raw sheep milk, coagulated with a plant rennet (Cynara cardunculus L.) and with a ripening period longer than 45 days, which received a Protected Designation of Origin (PDO) in 1995. Besides the PDO cheese, in the same geographical area other half-hard cheeses are also produced, primarily by the same firms, from raw mixed sheep and goat’s milk coagulated with an animal rennet. The name, Nisa, comes from the municipality of Nisa, which has been the most important and traditional centre of cheese economy in North of Alentejo (Graça, 1988). The geographical production area of “Queijo de Nisa” is in a less-favoured area of eight municipalities in the North of Alentejo and the regional dairy herd has 30,750 “merino” sheep, shared by 241 farmers. Agriculture plays a dual role, as provider both of food, and rural environmental and cultural services. It includes high nature-value farming systems, such as keeping sheep, goats and beef cattle, on wooded agro-pastoral land and Mediterranean scrub. In the geographical area we have identified three different types of cheese dairies, among processors of “Queijo de Nisa” and other processors. We have surveyed all the cheese dairies and we present the results of that survey. We compare these different types of cheese dairies in order to analyse the social, economic and territorial differentiation related to them

    Engaged in integrated reporting? Evidence across multiple organizations

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    Purpose: The purpose of this paper is twofold: to provide evidence on geographic and firm-level characteristics within organizations using integrated reporting (IR) methodology to communicate their business model to stakeholders; and to shed light on the contend of integrated reports of organizations that have been recognized as leading practice by a reputable award process or through benchmarking. Design/methodology/approach: Secondary analysis of data (descriptive and inferential statistics) is used for a sample of 224 organizations (79 classified as IR Reference Reporters and 145 as IR Regular Reporters) across 26 countries (2011 to mid-2015). Content analysis is used for IR Reference Reporters. Findings: Evidence for the first objective suggests that compared with IR Regular Reporters, the majority of the IR Reference Reporters are from Europe, are larger, have a higher market value, are more profitable and are less leveraged. Evidence for the second objective reveals that the guiding principles, fundamental concepts and content elements of the most recent integrated report published by each IR Reference Reporter (leading practice) seem less than expected. Research limitations/implications: IR Examples Database does not cover all of the organizations reporting according to the IR framework. Content analysis can be biased by authors’ interpretations. Practical implications: Potential benefit both to researchers and to those involved in the reporting of financial and non-financial information using the IR tool. Originality/value: The originality of the paper is as follows: it contributes to the international debate on the evolution from sustainability to IR, provides evidence on geographies and firm-level characteristics of organizations using IR to better communicate and provides the most prominent information disclosed by Reference Reporters.info:eu-repo/semantics/acceptedVersio

    Educação rodoviária: estudo de caso

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    A sinistralidade rodoviária transformou-se numa doença social, das principais causas de morte, internamentos, tratamentos prolongados e incapacidades permanentes. Com os programas de segurança rodoviária a sinistralidade rodoviária tem diminuído. Em que medida estes programas incluem a educação rodoviária? Na escolaridade obrigatória é (ou não) abordada a educação rodoviária? O que pensam os professores sobre esta temática nos currículos escolares? Usa-se o método comparativo na análise das orientações e programas internacionais sobre segurança rodoviária. Analisa-se em estudo de caso as representações de professores sobre a educação rodoviária nas escolas. A educação rodoviária constitui uma necessidade básica de aprendizagem para todos

    Barn owl feathers as biomonitors of mercury: sources of variation in sampling procedures.

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    Given their central role in mercury (Hg) excretion and suitability as reservoirs, bird feathers are useful Hg biomonitors. Nevertheless, the interpretation of Hg concentrations is still questioned as a result of a poor knowledge of feather physiology and mechanisms affecting Hg deposition. Given the constraints of feather availability to ecotoxicological studies, we tested the effect of intra-individual differences in Hg concentrations according to feather type (body vs. flight feathers), position in the wing and size (mass and length) in order to understand how these factors could affect Hg estimates. We measured Hg concentration of 154 feathers from 28 un-moulted barn owls (Tyto alba), collected dead on roadsides. Median Hg concentration was 0.45 (0.076-4.5) mg kg(-1) in body feathers, 0.44 (0.040-4.9) mg kg(-1) in primary and 0.60 (0.042-4.7) mg kg(-1) in secondary feathers, and we found a poor effect of feather type on intra-individual Hg levels. We also found a negative effect of wing feather mass on Hg concentration but not of feather length and of its position in the wing. We hypothesize that differences in feather growth rate may be the main driver of between-feather differences in Hg concentrations, which can have implications in the interpretation of Hg concentrations in feathers. Finally, we recommend that, whenever possible, several feathers from the same individual should be analysed. The five innermost primaries have lowest mean deviations to both between-feather and intra-individual mean Hg concentration and thus should be selected under restrictive sampling scenarios

    Power generation by unhealthy photovoltaic modules

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    Hotspots are one of many defects that can occur on degraded photovoltaic system, yielding a detrimental effect on the PV module production. Infrared thermography was used to detect and quantify the severity of hotspots. Temperature difference between overheated and healthy areas was assessed. Four PV modules were analysed, one of them presenting a hotspot. A model for both healthy and unhealthy PV modules was developed, based on the single diode solar cell model and considering, exclusively, data-sheet parameters. To validate the model, the outputs for these working conditions were compared with the real outputs of the studied PV modules, which were previously measured and stored. The relationship between the severity of a hotspot and its respective impact on the power generation of the PV module was studied and the consequent monetary loss can be assessed. Thermographic analysis was enhanced as an optimizing decision-aid tool for the operation of photovoltaic installations.publishersversionpublishe

    Structure determination of Split-soret Cytochrome from a Desulfovibrio species isolated from a human abdominal abcess

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    The determined structure of the split-soret cytochrome (SSC) isolated from Desulfovibrio desulfuricans ATCC 27774 (D.d.) revealed a new Heme arrangement, which suggests that this protein constitutes a new cytochrome class.. SSC is a 52.6kDa homodimer containing four hemes at one end of the molecule. In each monomer the two hemes have their edges overlapped within van der Waals contacts. The polypeptide chain of each monomer supplies the sixth ligand to the heme-iron of the other monomer. A similar protein was recently purified from a homologous Desulfovibrio clinical strain isolated from an abdominal wall abscess in human patient2. Crystals of this SSC were grown using vapour diffusion method in the presence of agarose gel. Diffraction data were collected using X-ray synchrotron radiation at the ESRF, beamline, ID 14-1. The structure will be solved by molecular replacement using the structure of the D.d. as a starting model
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