21 research outputs found

    Secondary school students’ understanding of sampling variability

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    PID2019-105601GB-I00/AEI/10.13039/501100011033, Research group FQM-126

    A remote sensing approach for regional-scale mapping of agricultural land-use systems based on NDVI time series.

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    In response to the need for generic remote sensing tools to support large-scale agricultural monitoring, we present a new approach for regional-scale mapping of agricultural land-use systems (ALUS) based on object-based Normalized Difference Vegetation Index (NDVI) time series analysis. The approach consists of two main steps. First, to obtain relatively homogeneous land units in terms of phenological patterns, a principal component analysis (PCA) is applied to an annual MODIS NDVI time series, and an automatic segmentation is performed on the resulting high-order principal component images. Second, the resulting land units are classified into the crop agriculture domain or the livestock domain based on their land-cover characteristics. The crop agriculture domain land units are further classified into different cropping systems based on the correspondence of their NDVI temporal profiles with the phenological patterns associated with the cropping systems of the study area. A map of the main ALUS of the Brazilian state of Tocantins was produced for the 2013-2014 growing season with the new approach, and a significant coherence was observed between the spatial distribution of the cropping systems in the final ALUS map and in a reference map extracted from the official agricultural statistics of the Brazilian Institute of Geography and Statistics (IBGE). This study shows the potential of remote sensing techniques to provide valuable baseline spatial information for supporting agricultural monitoring and for large-scale land-use systems analysis

    The active metabolite of leflunomide, A77 1726, inhibits the production of prostaglandin E2, matrix metalloproteinase 1 and interleukin 6 in human fibroblast‐like synoviocytes

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    Objectives. To investigate the effects of the active metabolite of leflunomide, A77 1726, on fibroblast‐like synoviocytes. In rheumatoid arthritis (RA) synoviocytes participate in tissue destruction by producing metalloproteinases (MMP), prostaglandin E2 (PGE2) and interleukin (IL) 6, which are involved in extracellular matrix degradation, resorption of the mineral phase and osteoclast‐mediated bone resorption. Methods. Human synoviocytes were stimulated with IL‐1α or tumour necrosis factor α (TNF‐α) in the presence of A77 1726. Culture supernatants were analysed for production of interstitial collagenase (MMP‐1), tissue‐inhibitor of metalloproteinases 1 (TIMP‐1), PGE2 and IL‐6. Total RNA was isolated and analysed for steady‐state levels of MMP‐1, cyclooxygenase‐2 (COX‐2) and IL‐6 mRNA. Results. A77 1726 inhibited the production of PGE2 in synoviocytes activated by TNF‐α and IL‐1α with median inhibitory concentrations (IC50) of 7 and 3 ”m respectively. In contrast, MMP‐1 and IL‐6 production was inhibited at high A77 1726 concentrations (> 10 ”m), whereas TIMP‐1 was not affected. The inhibition of MMP‐1 and IL‐6 production was due to the known inhibitory effect of A77 1726 on pyrimidine synthesis, as it was reversed by the addition of uridine. This did not apply to PGE2 production, which was inhibited via direct action of A77 1726 on COX‐2, as shown by the increasing amount of substrate (arachidonic acid) in the culture medium. Conclusion. This study shows that some of the beneficial effect of leflunomide in RA patients may be due to the inhibition of PGE2, IL‐6 and MMP‐1 production in synoviocytes. This effect, coupled with its multiple inhibitory effects on T lymphocyte functions, might account for the significant reduction in the rate of disease progression in RA patients treated with leflunomid

    Anålisis de la complejidad semiótica y el contexto de las tablas estadísticas en los libros de texto españoles de secundaria

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    El objetivo del presente trabajo es analizar el nivel de complejidad semiĂłtica, junto con los contextos en que se plantean de los propuestos por PISA, en las tablas estadĂ­sticas incluidas en una muestra de 18 libros de texto españoles dirigidos a la educaciĂłn secundaria de tres editoriales diferentes. Para ello se realiza un anĂĄlisis de contenido del tema de estadĂ­stica y probabilidad en cada texto seleccionado. Los resultados muestran la complejidad creciente del tipo de tabla estadĂ­stica al avanzar el curso escolar, siendo la tabla de distribuciĂłn de una variable la mĂĄs frecuente, especialmente la que presenta frecuencias ordinarias. El contexto que aparece con mayor fuerza es el personal y se observa tambiĂ©n un incremento de tareas sin contexto, especialmente en el Ășltimo curso de secundaria

    Sensoriamento remoto e anålise espacial: uma contribuição para o mapeamento dos sistemas integrados de produção agropecuåria.

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    No ano de 2009, o Governo do Brasil apresentou o Plano de Agricultura de Baixa Emissão de Carbono, cujo objetivo é a organização de açÔes para a adoção de tecnologias de produção de alimentos alinhadas aos compromissos de redução de emissÔes de GEE. Entre diversas pråticas destaca-se a implementação da integração lavoura-pecuåria (iLP). No entanto, a falta de procedimentos de monitoramento limita a governança do Plano. Os sistemas iLP podem ser adotados em duas abordagens distintas: Inter-anual e intra-anual. Este artigo tem como objetivo utilizar dados provenientes de sensoriamento remoto para identificar åreas de iLP na abordagem interanual no estado do Mato Grosso, na contribuição de um protocolo de monitoramento. Com o resultado, identificou-se que a implantação dos iLP tem seu auge em 2016 quando chega a 5% de toda årea de agricultura e pecuåria do estado do Mato Grosso

    Molecular phylogenetic analysis of nuclear genes suggests a Cenozoic over-water dispersal origin for the Cuban solenodon

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    The Cuban solenodon (Solenodon cubanus) is one of the most enigmatic mammals and is an extremely rare species with a distribution limited to a small part of the island of Cuba. Despite its rarity, in 2012 seven individuals of S. cubanus were captured and sampled successfully for DNA analysis, providing new insights into the evolutionary origin of this species and into the origins of the Caribbean fauna, which remain controversial. We conducted molecular phylogenetic analyses of five nuclear genes (Apob, Atp7a, Bdnf, Brca1 and Rag1; total, 4,602 bp) from 35 species of the mammalian order Eulipotyphla. Based on Bayesian relaxed molecular clock analyses, the family Solenodontidae diverged from other eulipotyphlan in the Paleocene, after the bolide impact on the Yucatan Peninsula, and S. cubanus diverged from the Hispaniolan solenodon (S. paradoxus) in the Early Pliocene. The strikingly recent divergence time estimates suggest that S. cubanus and its ancestral lineage originated via over-water dispersal rather than vicariance events, as had previously been hypothesised
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